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Breastfeeding, Fertility and SubFertility - Getting Pregnant and Avoiding Pregnancy

This is part 2 of a blog dealing with breastfeeding and fertility. Part 1 covered the menstrual cycle andhow breastfeeding affects the cycle and the gradual return of fertility during breastfeeding. In part 2 I will discuss birth control and trying to conceive while breastfeeding.

So let's start with birth control..

Breastfeeding as Birth Control

Breastfeeding is actually a very effective form of birth control in the months following birth, providing a few simple rules are followed. No contraceptive is 100% effective but breastfeeding is as effective as many other contraceptive methods and provides protection without side effects. Hormonal contraceptives while breastfeeding can potentially pose a risk to milk supply. If a woman's period has not yet returned, baby is exclusively breastfeeding and the baby is less than 6 months old then breastfeeding is 98-99% effective as a method of birth control. To compare that to other methods lets have a look at them side by side.

  Efficacy as Contraceptive
Male Condom
Female Condom
Contraceptive Pill
Progesterone Only Pill

These figures assume that each of the methods will be used correctly, and for breastfeeding that means that each of the 3 rules are followed. If any of them are not met and you want to avoid pregnancy, then consideration of additional contraception may be needed. It may be that for some women it will take several more cycles until they reach full fertility, but others may move through the stages described in Part 1 of the blog very quickly. Tracking your cycle will give you a better idea of what stage of fertility you have reached, and I will cover that later in this article.

If you decide to add another method of contraception along side breastfeeding then here is a word of caution around hormonal methods. It is recommended that a progestin only option is used. For most mothers using a progestin only contraceptive, after 6 weeks post partum provides effective protection without detrimentally affecting milk production. The 6 week figure is important as milk supply is establishing and building throughout the first 5 weeks, and milk production can be significantly affected by altering the hormonal balance during this period.

Although most women find no problem with milk supply on progestin after 6 weeks, it is important to note that a significant minority of women do find that their milk supply drops while on a progestin contraceptive. Any kind of hormonal alteration has the potential to affect milk production, and its important to consider this carefully, particularly before using any kind of longer term contraceptive such as an implant. If you do choose a hormonal method of birth control, you can watch out for signs of fussiness, softer breasts or lower weight gain in your baby which may indicate a drop in milk production.

Wanting to Conceive while Breastfeeding

Conceiving while breastfeeding can be a very different experience for different women. Some women can find that they conceived their first child easily and quickly, but find it very difficult to conceive while breastfeeding. Some others, in contrast, find no issue with getting pregnant while nursing more than one child. Before we look at this specifically I think its useful to set some context around the timings of when we expand our families. Here in NI, only 11.7% of babies are still breastfed at 6 months (2013-14 figures from the NI assembly briefing paper on breastfeeding attitudes). This means that the vast majority of women are not breastfeeding at 6 months post partum and will be fully fertile. This is not the biological norm and gives an unrealistic expectation of when fertility should return. We know from Part 1 that the average time that menstruation returns while breastfeeding on cue is after 14 months, and that for some women it will be much later. We also know that women often remain subfertile for some time after menstruation returns. This is part of the normal reproductive process, and makes sense when you think of it from a biological standpoint.

It takes an enormous investment of physical and psychological resources in order to create and grow a completely new human, then to birth and raise that person. While breastfeeding we are asking the body to provide enough energy and resources to maintain ourselves and also grow and maintain our nursling. This requires a lot of energy, in fact the lactating breast uses more energy than the brain! When we want to conceive while breastfeeding, we are asking the body to be able to maintain ourselves, to sustain our nursling and to create and grow a whole new human on top. In simplest terms, our fertility returns when our body is able to do all of this without detriment to ourselves. When a baby is exclusively feeding, and therefore has intense needs physically (both in milk production and general parenting) and emotionally, we generally remain infertile. As the baby/toddler feeds less and less we have more energy available which could be used for fertility, and so our fertility returns.

The timing between our children biologically is often determined by what is safest for us. Our body allows us to conceive and carry to term when we have the biological reserves to do this and to be able to raise our young. Reproduction is a very energy intensive process for any animal, and we do know from studies that both women and children have better pregnancy and birth outcomes when pregnancies aren't too close together. The WHO report on child spacing recommends waiting at least 2-3 years between birth and subsequent pregnancy, and recognises that some studies suggest that 3-5 years is better. The report states:

After a live birth, the recommended interval before attempting the next pregnancy is at least 24 months in order to reduce the risk of adverse maternal, perinatal and infant outcomes.
[such as]elevated risk of infant, neonatal and perinatal mortality, low birth weight, small size for gestational age, and pre-term delivery.

Very close birth to pregnancy intervals, it also explains, are associated with greater risk of maternal mortality. It takes time after a birth to rebuild body stores used in pregnancy. Iron stores, for example take around 18 months post-partum to rebuild to pre-pregnancy levels. This is very important as anaemia in pregnancy creates risk for both the mother and the baby. In fact the longer your menstruation is delayed by breastfeeding, the less blood and iron you lose, which is beneficial to iron stores. They also found that less than 18 months between birth and getting pregnant led to a 20% higher death rate after the age of 50 for the women, and more illness in later life.

Babies are also hard work. A report from Catalyst Consortium in conjunction with USAID on child spacing found that each infant a woman had increased her work burden by 2 hours per day. Each preschool child, in contrast, only increased the burden by 52 minutes. So an infant was twice as much work as a preschooler. They state,

If births were spaced at least three years, allowing the index child to reach preschool age before the birth of the next infant, she can potentially decrease domestic burden and have more time and energy to care for herself and her family.

If your period has not yet returned and you are feeling anxious about wanting to try for another baby it's worthwhile remembering why it has not returned, and that it is likely that the demands on your body are very high right now. The amount that your baby is feeding is part of this, and your baby may need this amount of suckling. We know that 92% of women get their period back by 2 years post-partum. It is worth considering whether now is the right time, or whether waiting a few more months is something that might work for you. For many couples, a few months for your toddler to mature will likely mean that he/she will naturally reduce feeding, and this reduction will reduce the demands on your body, and allow your fertility to return. In fact this is more normal culturally as well. Although in our part of the world most women's fertility might return earlier than is biologically normal, in fact child spacing intervals are still per the WHO recommendations. The average birth spacing in the UK over the years 2001-2012 was 37 months (Office of National Statistics).

If you have considered waiting longer but in your circumstances feel that it is important to conceive more quickly, there are ways to increase your chances.

If you are not menstruating

The first and perhaps most obvious consideration in getting pregnant is that you must be ovulating. You cannot get pregnant unless an egg is maturing and being released. In general you will need to have had a period before ovulating. On internet forums you will likely get people telling you that you can catch "the first egg" and get pregnant before you ever have a period. Although this is possible, the reality is that it is unlikely. For most women it's unlikely that the hormones associated with the first egg will be able to maintain a pregnancy. McNeilly, 2001 says,

Often while women continue to breast-feed the first few ovulations and menses are associated with inadequate corpus luteum function, which would probably not support a pregnancy

Although you may be one of the lucky couples who gets pregnant during the first cycle, it's important to realise this experience is not that of most couples. For most, it takes a few cycles in order for fertility to get to a level where you can conceive and then maintain that pregnancy. In fact a study by Howie & McNeilly in 1982 found that in 55% of breastfeeding women ovulation didn't happen at all during their first menstrual cycle. It did occur in 66% of later cycles.

If you are breastfeeding, not yet menstruating and want to get pregnant, the first step is to restore a regular menstrual cycle. As we know from Part 1, the lack of menstruation is due to the amount of time a baby spends suckling, so in order to restore it we need to reduce the amount of suckling. For an older toddler this may just mean a little alteration to the day. It may be as simple as avoiding the favourite feeding chair, or organising lots of toys and activities and playing together during the day to provide connection in other ways alongside making sure there are lots of snacks, meals and other drinks available. For a younger child, it might require more of a weaning type approach. The right approach for you will depend on the age of your baby and your own baby's sucking needs and the nursing rhythm you are in right now. One toddler of 18 months might only be feeding morning and night for example, whereas another may be having a number of feeds during the day and night time. The important thing to remember is that it is the amount of suckling which seems to be important - the time involved. So feeding 4 times a day for 10 minutes will be better for your fertility return than feeding 3 times a day for 20 minutes at each feed. This means that just shortening feeds may be enough to have an effect for you. I want to reiterate here that I am talking about toddlers. Shortening a feed for an 18 month old is very different to shortening a feed for an 8 month old who is much more reliant on the calories from breastmilk.

Many mothers do find that creating a longer gap at night between feeds is very effective at returning their cycles, with many finding that a 6-8 hour gap seems to be enough. It used to be thought that this was due to prolactin levels during the night, but McNeilly's research seems to suggest that prolactin's role isn't exactly clear and it is more likely the drop in sucking stimulus.
I will add more links on reducing feeding and tinkering with the nursing rhythm in the Further Reading Section, but do contact an IBCLC or breastfeeding counselor to talk through options, who will be able to talk you through gentle weaning techniques. Any reduction in feeding can be emotional for both you and your baby, and there are ways to approach it gently and with love.

If you are having regular periods

If you are having regular periods, then it is likely that you are ovulating, however it's also likely that your cycle isn't quite the same as it was before you got pregnant without breastfeeding. Howie & McNeilly found that when periods returned in the breastfeeding women they studied, the cycles were on average 37 days long. Formula feeding women in comparison had cycles of 29 days. It is more likely that the extra days are part of the follicular phase of the cycle (see Part 1 of the blog for details). When a cycle is longer than usual, it is often that it has taken longer to build up the oestradiol levels to trigger ovulation. The luteal phase does not usually increase in length. When breastfeeding (which we know lowers our oestradiol levels) it makes sense that it could take longer to mature an egg.

This means that if you now find that your cycle is 32 days, you can't assume that you are ovulating on day 14 (which many websites / and sometimes GPs) will assume. You may be ovulating on day 18 with a 14 day luteal phase, or you may be ovulating on day 22 with only a 10 day luteal phase. If the latter is the case, you may be having regular 32 day cycles for many months, but will find it extremely difficult to get pregnant with that 10 day luteal phase. So if you are having regular periods it can help to track those cycles. Tracking will give you a good sense of where you are in the process of moving from subfertility to fertility. Once you know when exactly you are ovulating, and how long your luteal period is, you will have a good sense of whether you are fully fertile, or if a few more changes are needed.

Tracking Your Cycle

Most of us aren't taught how our bodies indicate our fertility status. In fact there are fertility signs that virtually all ovulating women can track, which can be used to determine when you are fertile and when you have ovulated.

1. Tracking ovulation

One of the easiest ways to track ovulation is using your waking temperature. Once you have ovulated body temperature typically rises by around 0.5 deg celsius. Before ovulation temperature averages 36.1-36.4 deg celsius, and afterwards it averages 36.4 - 37.1 deg celsius due to the increased progesterone. As we know from Part 1, progesterone rises significantly after ovulation and drops when the corpus luteum degrades. Basal body temperature (BBT) follows this progesterone curve and it is easy to see on a chart if it is plotted daily. Over a couple of cycles this will help you to determine how long your luteal period is and whether it could be an issue in conceiving. Can't you just tell this by using an OPK (ovulation predictor kit)? Well the key here is that an OPK is predictor. It simply tells you when there has been a surge in LH and that ovulation is likely to happen in the next 24-48 hours. During the process of returning fertility however you can have a surge but it just never quite gets to a level that causes an egg to release, and as the quote from McNeilly above shows, ovulation isn't guaranteed while breastfeeding. Tracking temperature will let you know if ovulation actually happened or not.

2. Cervical Fluid

For a few days before ovulation, due to the rising oestrogen levels women produce large amounts of fertile mucus. This changes the acid/alkaline levels of the vagina so that sperm can survive and reach the egg. This mucus resembles raw egg white, and on internet forums you will often see this referred to as EWCM (Egg White Cervical Mucus). Immediately after ovulation this dries up, so is an indicator not just of impending ovulation, but of when it has happened. When ovulating regularly you will find through tracking over a few cycles, the number of days you have EWCM, when you ovulate and how long your luteal period is. If you are not ovulating regularly yet, you may find that in a cycle you have a couple of stages where you have EWCM, and then less, then more again where your body tries to ovulate. If you are having very long cycles and several stages where your body is trying to ovulate, it may be that reducing sucking slightly more will allow ovulation to happen a little earlier.

Tracking is simple, but a much larger topic that can be dealt with on this blog. A fabulous resource on this is Toni Weschler's book "Taking Charge of Your Fertility" which I will link below.

Normalising Cycles & Supplements

After tracking many women who are breastfeeding find that they have a shortened luteal phase (between ovulation and next period). This can make it more difficult to get pregnant, particularly if it is less than 11 days. Some practitioners suggest supplements which can support the body in production of progesterone. Marilyn Shannon (Fertility, Cycles & Nutrition) suggests that 200-600mg of Vitamin B6 a day can be helpful. There can be side effects to taking large doses of B6, so it is sensible to talk this through with a nutritionist before beginning. Ideally we would get our vitamin needs through whole foods, so looking at diet before considering supplements is always sensible.

Many women also take the herbal supplement Vitex / Agnus Castus in order to increase progesterone levels and there are studies which show it to be effective in the treatment of luteal phase defect due to high prolactin (Milewicz et al 1993). If vitex /agnus castus is taken to increase progesterone and you then get pregnant however you then need to decide what to do. If you stop the supplement you may cause a drop in progesterone which may be a risk for miscarriage. If you continue it you may interfere with the pregnancy hormone levels. Many women wean off the supplement once they are pregnant. Before starting it in order to conceive it is worth having thought this through and having decided what your approach would be.

Just a word of caution on some of the foods/herbs commonly suggested in fertility forums. Common foods and supplements that are mentioned are Maca and perhaps Red Clover for increasing oestrogen and Vitex/Agnus Castus for increasing progesterone. Each of these foods are technically known as adapatogens. Adaptogens modulate function in the body and are supposed to provide balance, but they can work differently in different people. Maca and Red Clover are often suggested for example in order to stimulate earlier ovulation. In fact in some people (and I have known this to be the case) they seems to delay ovulation. A 1979 study on red clover in sheep (Kelly et al) found that ovulation rates were lower for the sheep grazing on red clover. The sheep were less rather than more fertile.

On Vitex / Agnus Castus - some studies show that it lowers prolactin (Milewicz et al 1993) whereas others show that it that it actually increases milk supply. Some studies suggest that it has different effects depending on the dosage. Anecdotally I have seen these differences in women, and have known some who found it normalised their cycles when taken after ovulation, and to delay/prevent ovulation when taken before ovulation. Other women find it normalises their cycles to take it daily throughout the cycle.

Before adding any of these supplements into your diet it may be wise to talk to a herbalist.

General Hormone Support

If you are finding your cycle just isn't where you want it to be, it's also worth looking at your diet and lifestyle in respect of hormone production and support. Healthy fats in the diet are essential for producing hormones. This is why female athletes with very low body fat, and a low fat diet often find that their menstrual cycle stops, so looking at your omega oil consumption is helpful (particularly DHEA and EPA). Good quality proteins are also important. Vitamin C is also a factor, as some studies have shown consuming Vitamin C promotes proper oestrogen production.

Sleep & Stress are 2 factors which I feel are vital in breastfeeding mothers also. When we are stressed we produce cortisol, and that can directly affect our hormones, since the body may actually produce the cortisol instead of progesterone, or may actually turn our progesterone into cortisol. Sleep deprivation is a stressor for the body, and very many mothers don't get enough sleep. Part of this is about parenting, but part of it is simply our culture and lifestyle and use of artificial lights and devices. In fact some estimates suggest we sleep 500 hours less than our ancestors per year. So prioritise sleep. Trying to conceive can itself be stressful, if it isn't happening for you when you want. Each cycle can be a rollercoaster of tracking, trying, and the dreaded 2 week wait, anticipation, hope and deep disappointment. Working on managing your stress through conscious relaxation, mindfulness or hypnotherapy, exercise and yoga can all be helpful, as can looking at therapies which relax like reflexology, CST, reiki etc.

None of it is Working

If you are tracking, and have reduced feeding somewhat and are still not seeing a cycle similar to pre-pregnancy, or have a persistently short luteal phase, it may be that breastfeeding is still having a significant effect on your fertility. We are all very different, and our bodily resources are different. We have different levels of stress, we parent differently and our body shapes and types differ. Age may also play a role and many of us are having our children older now when hormones and hormone production may be working not quite as efficiently as it did 10 years earlier.

If your current nursling is under 2, you may just need to give it a little more time. The WHO recommend feeding for 2 years and beyond, and for most women their fertility will return with just a little time. For some women however, even after this time breastfeeding is a barrier to conceiving. McNeilly says:

After the return of menstruation during lactation, the frequency of ovular cycles progressively increases but does not return to normal until complete weaning has taken place.

Breastfeeding always exerts some effect on the hormones and for some women, weaning is needed to conceive again. This can be very difficult and emotional to confront, as if you have fed into toddlerhood you already feel the importance of breastfeeding for both you and your toddler. Breastfeeding may feel integral to your sense of mothering, and it can be extremely conflicting to feel that this thing that is such an important part of your mothering (breastfeeding) is preventing you from becoming a mother again. If you find yourself in this situation and feel like you need to wean in order to conceive again, do remember that there is no right and wrong in this situation. You may have wanted your child to self wean, and feel a sense of guilt. It's important to weigh this up against what your child can gain from having a sibling. It's also important to feel at peace with your decision to wean in case a further pregnancy doesn't happen even after weaning. There are very many conflicting thoughts and feelings if you do find yourself in this situation and it can really help to talk through your thoughts with an IBCLC / breastfeeding counselor or fertility counselor who can help you work through your thought process with sensitivity and support. In much of nature animals do not come 'into heat' or resume fertile status until their nursling has weaned, so it is not unususal for this to be the case. If we had a larger population of women feeding until 2 in our society, we may find that it is larger population who find themselves in this situation. There is no right or wrong decision about whether to wean, there is just the 'right decision for you'.

In Part 3 I'll look at breastfeeding after you have conceived, risk / safety in pregnancy and whether breastfeeding may affect miscarriage risk.

If you have any questions about a consultation or would like to arrange to meet, please get in touch.

Further Reading

Useful websites:
Taking Charge of Your Fertility:


About the author

Carol Smyth

I am an IBCLC (International Board Certified Lactation Consultant) in private practice in Northern Ireland and a La Leche League Leader with La Leche League of Ireland

Important Information

All material on this website is provided for educational purposes only. Online information cannot replace an in-person consultation with a qualified, independent International Board Certified Lactation Consultant (IBCLC) or your health care provider. If you are concerned about your health, or that of your child, consult with your health care provider regarding the advisability of any opinions or recommendations with respect to your individual situation.