Once you resume sex after giving birth, use contraception; breastfeeding is not contraception; if you want another baby, wait at least 18 months before getting pregnant

Cost

A box of condoms is a few dozen CNY. An IUD or implant needs a hospital visit, and the price varies by place. The hard part is that things are hectic after birth and this gets overlooked.

What you get

The UK's National Health Service (NHS) says you can get pregnant again as early as 3 weeks after having a baby, even if you are breastfeeding and your periods have not returned. Unless you want another baby right away, use contraception every time you have sex. Relying on breastfeeding for contraception is called the lactational amenorrhea method, and it requires all three at once: breast milk only, no period, and a baby under 6 months. Followed strictly, it prevents over 99% of pregnancies. Among those who cannot follow it that strictly, about 2 in 100 get pregnant within 6 months. If any of the following happens, switch to another method: the baby is over 6 months, you start formula or solid food or use a pacifier, your period has come back (even light bleeding counts), you stop feeding at night, or you feed less often. A pooled analysis combined 67 studies and adjusted for the mother's age and family circumstances. Taking an interval of 18 to 23 months from one birth to the next conception as the reference: for under 6 months, preterm birth OR 1.40 (95% CI 1.24–1.58, the plausible range), about 40% higher. Low birth weight 1.61 (1.39–1.86), small for gestational age 1.26 (1.18–1.33). Intervals of 6 to 17 months and over 59 months were also higher on all three. A Canadian study looked at more than 148,000 (14.8万) pregnancies and compared an interval of 6 months with one of 18 months. For mothers 35 and older, maternal death or severe illness was 0.62% versus 0.26%, aRR 2.39 (2.03–2.80), about 2.4 times. For mothers 20 to 34 there was no difference (0.92, 0.83–1.02). For babies of mothers 20 to 34, stillbirth, infant death, very small size or very preterm birth together were 2.0% versus 1.4%, aRR 1.42 (1.36–1.47). A 2005 World Health Organization expert meeting recommended waiting at least 24 months after a birth before trying for the next pregnancy. What the experts all agreed on was that getting pregnant in under 18 months should be avoided. After a miscarriage or induced abortion, wait at least 6 months.

Notes

A dispute. How long is long enough is stated differently. Among the World Health Organization's experts, one camp argued for 18 months and one for 27 months, and 24 months was the compromise between the two. The NHS says at least 12 months. An Australian study compared the two intervals of each of 40441 mothers with each other and reached a different conclusion. For an interval of 0 to 5 months, preterm birth OR 1.07 (0.86–1.34) and low birth weight 1.03 (0.79–1.34), and no difference was seen in either. When the comparison was between different mothers, preterm birth was 1.41. So part of the risk of a short interval may come from the mother's own circumstances. Contraception itself is not in dispute; what is disputed is only how long to wait. According to the NHS, condoms and the implant can be used right after birth, including while breastfeeding. For someone breastfeeding, the combined pill generally has to wait until at least 6 weeks after birth. Which to use, talk it over with the doctor at the 42-day postpartum checkup; see §27.16 (the checkup at 42 days postpartum). The size of the benefit is rated “medium” by judgment, with the reasoning in the verification record. The benefit falls on you and your next child.

Evidence grade

B : Supported by research but without a precise number, or based on small or single studies.

Sources

1. NHS. Sex and contraception after birth. https://www.nhs.uk/baby/support-and-services/sex-and-contraception-after-birth/
2. NHS. Natural family planning. https://www.nhs.uk/contraception/methods-of-contraception/natural-family-planning/
3. Conde-Agudelo A, Rosas-Bermúdez A, Kafury-Goeta AC (2006). Birth spacing and risk of adverse perinatal outcomes: a meta-analysis. JAMA, 295(15), 1809. https://doi.org/10.1001/jama.295.15.1809
4. Schummers L, Hutcheon JA, Hernandez-Diaz S, et al. (2018). Association of Short Interpregnancy Interval With Pregnancy Outcomes According to Maternal Age. JAMA Internal Medicine, 178(12), 1661. https://doi.org/10.1001/jamainternmed.2018.4696
5. World Health Organization (2007). Report of a WHO Technical Consultation on Birth Spacing, Geneva, 13–15 June 2005（WHO/RHR/07.1）. https://www.who.int/publications/i/item/WHO-RHR-07.1
6. Ball SJ, Pereira G, Jacoby P, de Klerk N, Stanley FJ (2014). Re-evaluation of link between interpregnancy interval and adverse birth outcomes: retrospective cohort study matching two intervals per mother. BMJ, 349, g4333. https://doi.org/10.1136/bmj.g4333（备注里的反方研究）

Translated from the Chinese original. Original book, section 27, tip 20. This section is about health and medicines. It is general information, not a substitute for a doctor’s diagnosis or prescription. Content may be out of date and rules differ by place. When you actually deal with an agency, a doctor or a court, follow what local officials, doctors and lawyers tell you. Disclaimer