The time interval between pregnancies may affect the risks of the subsequent pregnancy. Research showed that both short and long inter pregnancy intervals has been associated with adverse or suboptimal outcomes. There are many other confounding factors or isolated unrelated factors that could play a role in the outcome of a pregnancy and one must be careful to draw conclusions. Proper advice on what is best for the individual has remained controversial since there is no consensus on what is ideal. You, however, have some control over the spacing of your pregnancies and this decision could potentially reduce the risks in a future pregnancy. It is important to plan ahead and make informed decisions before attempting to fall pregnant again.
What is the definition of a short and long inter pregnancy interval?
There is no uniform international definition regarding pregnancy spacing. The inter-pregnancy interval is the spacing between your previous birth and the beginning of the following pregnancy. If you fall pregnant within 6 months it is regarded as a short inter-pregnancy interval, while 5 years is seen as a long interval.
What are potential medical risks of a short inter pregnancy interval?
Closely spaced pregnancies might not give your body enough time to recover from your previous pregnancy. Pregnancy and breastfeeding can deplete your stores of nutrients, especially folate and iron and if you fall pregnant before replacing these stores it could affect your health or your baby’s health. It is also possible that if there is inflammation in the genital tract following a pregnancy, then closely spaced pregnancies would not offer your body enough time to completely heal and this could increase risk.
A short inter-pregnancy interval is therefore associated with an increased risk of maternal aneamia, higher risk of preterm labour, as well as low birth weight babies. The chances of a successful vaginal birth after a previous caesarean section are also decreased.
What are potential risk of a long inter pregnancy interval?
It is thought that the changes your body goes through during pregnancy can improve the capacity of your uterus to promote growth of the baby and offer support to the developing baby. These beneficial changes could regress over time and a future pregnancy would no longer be able to benefit from these changes.
An interval between pregnancies of more than 5 years does increase the risk of high blood pressure and pre-eclampsia in a subsequent pregnancy.
What are other factors to consider?
When we look at research and the apparent association between pregnancy spacing and the risk of complications during a subsequent pregnancy, it is important to stay realistic and acknowledge that unmeasured, confounding factors could also play a role.
The common factor from research, however, is that most of the adverse effects have been associated with a short inter-pregnancy interval.
There is no perfect time to have another baby and choosing when to have another baby is a personal decision. You might consider various factors in addition to the health risks and benefits discussed above. These could include how the age gap will impact on your family life, career, financial situation, as well as your other children.
It is important to use reliable contraception until you make a decision about when to have another child.
The 6 week post-partum visit will be used to discuss your most recent pregnancy and guidance on how to positively influence the outcome for you and your baby in a future pregnancy, will be addressed.
If you are approaching 35 years of age, it is important to balance the increasing risk of subfertility with advancing age with the increased risks of pregnancy complications associated with a very short inter-pregnancy interval.
Have a look at this interesting perspective from recent research and watch the short video: https://doi.org/10.1136/bmj.g4333 .
Here they argue that much of the variation in birth outcomes we see in practice, might be explained by risk factors that vary greatly between individual women, but tend to persist between pregnancies, such as genetic predisposition, lifestyle, or social conditions.
How can I lower my risk during a future pregnancy?
Discuss the way forward at your 6 weeks postnatal checkup.
Take reliable contraception until you have made an informed decision.
Schedule a preconception visit before falling pregnant to discuss the latest research applicable to your individual situation.
Stay active and follow a healthy diet.
Is there more specific guidance for my personal situation?
You can generally plan to fall pregnant again after 18 months to 2 years, if you are younger than 35 years and the last pregnancy was uncomplicated with your baby born vaginally at term. If you are 35 or older you should wait 12 months.
It is generally advised to wait 12 months after a caesarean section. Falling pregnant within 6 months can have significant risks.
It is best to wait for 12 months after a previous preterm birth, but waiting longer than 18 months is ideal according to the latest research. Falling pregnant within 6 months has significant risks.
It is best to wait 12 months or more after previous pre-eclampsia.
The risks and recommendations don’t apply to couples who have had a miscarriage, as long as you are healthy and feel ready. After a stillbirth it is normally advisable to wait 15 months.
What is the bottom line?
Schedule a preconception visit before falling pregnant again and use reliable contraception till the time is right.