Although the World Health Organisation recommends at least a six-month gap after a miscarriage/abortion before falling pregnant, researchers say there does not appear to be any extra risk for either mother or baby in conceiving again within a few months.
The study in PLOS Medicine, analysing 72 000 conceptions, suggests couples might safely try sooner for a baby, with the British baby loss support charity Tommy’s saying women who feel ready to try again immediately after a miscarriage should do so if there is no medical reason against it.
The WHO says more research into pregnancy spacing is already under way and would inform any future updates to the advice, reports the BBC.
The research from Norway, spanning eight years from 2008 to 2016, found no major differences in outcomes when a new pregnancy happened sooner than a six-month delay. The findings differ from earlier work in Latin America that – along with other studies – informed the WHO recommendations on pregnancy spacing.
The authors of the latest analysis (mostly from the Norwegian School of Public Health) say the advice needs reviewing so that couples can make an informed decision about when to try for a baby.
Asking parents to wait six months after a miscarriage or an abortion may be unacceptably too long for some, particularly when the emerging medical evidence does not appear to support it, they say. They recommend more studies.
Pregnancy after miscarriage
Experts agree that being in good health increases the chance of conceiving. Women are advised to take folic acid tablets daily while trying to get pregnant and up until 12 weeks of pregnancy.
Early miscarriage happens to about one in five women in their lifetime. Often, no cause is found.
After one miscarriage there is usually a very good chance that the next pregnancy will be successful as recurrent miscarriage is rare.
Study details
Interpregnancy interval and adverse pregnancy outcomes among pregnancies following miscarriages or induced abortions in Norway (2008–2016): A cohort study
Gizachew Tessema, Siri Håberg, Gavin Pereira, Annette Regan, Jennifer Dunne, Maria Magnus
Published in PLOS Medicine on 22 November 2022
Abstract
Background
The World Health Organization recommends waiting at least six months after miscarriage and induced abortion before becoming pregnant again to avoid complications in the next pregnancy, although the evidence-based underlying this recommendation is scarce. We aimed to investigate the risk of adverse pregnancy outcomes (preterm birth (PTB), spontaneous PTB, small for gestational age (SGA) birth, large for gestational age (LGA) birth, preeclampsia, and gestational diabetes mellitus (GDM)) by interpregnancy interval (IPI) for births after a previous miscarriage or induced abortion.
Methods and findings
We conducted a cohort study using a total of 49 058 births after a previous miscarriage and 23 707 births after a previous induced abortion in Norway between 2008 and 2016. We modelled the relationship between IPI and 6 adverse pregnancy outcomes separately for births after miscarriages and births after induced abortions. We used log-binomial regression to estimate unadjusted and adjusted relative risk (aRR) and 95% confidence intervals (CIs). In the adjusted model, we included maternal age, gravidity, and year of birth measured at the time of the index (after interval) births. In a sensitivity analysis, we further adjusted for smoking during pregnancy and prepregnancy body mass index. Compared to births with an IPI of 6 to 11 months after miscarriages (10.1%), there were lower risks of SGA births among births with an IPI of <3 months (8.6%) (aRR 0.85, 95% CI: 0.79, 0.92, p < 0.01) and 3 to 5 months (9.0%) (aRR 0.90, 95% CI: 0.83, 0.97, p = 0.01). An IPI of <3 months after a miscarriage (3.3%) was also associated with lower risk of GDM (aRR 0.84, 95% CI: 0.75, 0.96, p = 0.01) as compared to an IPI of 6 to 11 months (4.5%). For births after an induced abortion, an IPI <3 months (11.5%) was associated with a nonsignificant but increased risk of SGA (aRR 1.16, 95% CI: 0.99, 1.36, p = 0.07) as compared to an IPI of 6 to 11 months (10.0%), while the risk of LGA was lower among those with an IPI 3 to 5 months (8.0%) (aRR 0.84, 95% CI: 0.72, 0.98, p = 0.03) compared to an IPI of 6 to 11 months (9.4%). There was no observed association between adverse pregnancy outcomes with an IPI >12 months after either a miscarriage or induced abortion (p > 0.05), with the exception of an increased risk of GDM among women with an IPI of 12 to 17 months (5.8%) (aRR 1.20, 95% CI: 1.02, 1.40, p = 0.02), 18 to 23 months (6.2%) (aRR 1.24, 95% CI: 1.02, 1.50, p = 0.03), and ≥24 months (6.4%) (aRR 1.14, 95% CI: 0.97, 1.34, p = 0.10) compared to an IPI of 6 to 11 months (4.5%) after a miscarriage. Inherent to retrospective registry-based studies, we did not have information on potential confounders such as pregnancy intention and health-seeking behaviour. Furthermore, we only had information on miscarriages that resulted in contact with the healthcare system.
Conclusions
Our study suggests that conceiving within three months after a miscarriage or an induced abortion is not associated with increased risks of adverse pregnancy outcomes. In combination with previous research, these results suggest that women could attempt pregnancy soon after a previous miscarriage or induced abortion without increasing perinatal health risks.
BBC article – Pregnancy soon after miscarriage no more risky – study (Open access)
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