Imagine turning up to your six-week postnatal check, only to discover you’re pregnant again. While uncommon, it can and does happen. Here’s what you need to know about postnatal contraception.
Women who have just had a baby may fall pregnant again sooner than they expect. The technical term "rapid repeat pregnancy" refers to the fact that an unexpectedly early pregnancy can impact significantly on both the mother and the baby. It is therefore important for women, from teens to those in their 40s, to be informed about postnatal contraceptive options.
Women who are not breastfeeding may ovulate as early as 28 days after delivery. They can therefore become pregnant again as early as 21 days after childbirth because sperm, at least the very determined ones, can survive for up to seven days in the female genital tract. The female egg is not so long-lived and only survives for about 24 hours after its release from the ovary.
For some women who have recently given birth, sex may be low on the priority list but for women who have resumed sexual activity, waiting to discuss contraception at the postnatal six-week check may be too late!
Options if you're breastfeeding
Breastfeeding can protect against pregnancy but it is not 100 per cent effective. Breastfeeding delays the return of the first ovulation and the onset of periods due to the effect of the "breastfeeding" hormone called prolactin. In breastfeeding women, the average time from delivery to the first ovulation is 33.6 weeks but it can vary from 14 to 51 weeks.
For breastfeeding to protect against another pregnancy it must be less than 6 months since the delivery, the woman must not have had a period yet and the baby must be "fully breastfed". This means no supplementary foods and intervals between feeds of no longer than about four hours during the day and six hours at night. Just to add to the challenge, we know that many women release their first egg before their first period so they may be unaware their fertility has returned.
Luckily Australian women, unlike many women around the world, have additional contraceptive options compatible with breastfeeding. These options have no negative effect on breastmilk or infant growth and development:
- Barrier methods such as condoms or a diaphragm. If breastfeeding’s impact on hormone levels leads to vaginal dryness, use water-based lubricants to make intercourse more comfortable.
- Progestogen-only pills (sometimes called mini-pills). The catch is these pills need to be taken within the same three-hour window each day.
- Longer-acting contraceptives such as the implant or injection. The implant is a small rod inserted under the skin of the upper arm. It lasts for up to three years but its effects are immediately reversible on removal. The injection is given every three months – however, its contraceptive effects are not immediately reversible so it can take up to a year for fertility to return to normal.
- An intrauterine device (IUD). Modern devices have come a long way from old-style IUDs and are rightfully gaining popularity amongst Australian women. IUDs provide reversible contraception which is also cost-effective because of their long-term use (up to five or even 10 years). Copper IUDs are a good choice for women who can’t use, or prefer not to use, a hormonal contraceptive method. The newer hormonal IUD releases a tiny amount of progestogen hormone into the uterus, the equivalent dose of just two progestogen-only pills a week. This can result in irregular spot bleeding to start with but most women end up with very light periods.
Options if you're bottle feeding
So what about contraception for women who are not breastfeeding? All the methods described so far contain either no hormones or only progestogen. They do not contain oestrogen. Any of these methods can be used by non-breastfeeding women but they also have the option of using a method containing oestrogen. Oestrogen-containing contraception is not recommended for breastfeeding women, at least for the first six months, although this reflects a lack of evidence about its effect on breastfeeding rather than any direct evidence of harm.
Oestrogen containing contraception includes combined oral contraceptive pills as well as the newer hormonal vaginal ring. Oestrogen-containing contraceptive pills have been used by Australian women for just over 50 years and remain a popular and effective choice. They carry a small risk of developing a blood clot in the veins, called a deep vein thrombosis or DVT, although this is much lower than the risk of developing a DVT as a result of pregnancy itself. The chance of developing a blood clot, usually in the legs or lungs, continues into the postnatal period. Therefore neither combined pills nor vaginal rings are advised earlier than 21 days from the birth. Women who are at additional risk of blood clots due, for example, to obesity, older age or smoking may be advised to defer starting the combined pill or vaginal ring until 6 weeks after delivery.
So to conclude, there are plenty of contraceptive options for the postnatal period and women can talk to their doctor or family planning clinic to work out which is the best fit for them. Considering the options early, even before delivery, is a useful approach since the contraceptive method that suits a woman best before a pregnancy may be very different to the best method after the baby is born and life becomes more unpredictable.
Dr Deborah Bateson is the Medical Director of Family Planning NSW