Is It Too Soon For Another Baby? The Research Speaks

Hillary Bennetts

Is It Too Soon For Another Baby? The Research Speaks

Table of contents

  • Intro
  • How Does It Affect Mom?
  • How Does It Affect Baby?
  • Is There an Ideal Timing?
  • Emotional Readiness vs. Physiological Readiness

0 min read


We know that women are having babies later in life these days and as a result, many are choosing to shorten the interval between babies. There are lots of considerations when it comes to pregnancy timing, and even more when trying to coordinate two or more children - do you want both babies in diapers at one time, or to transition one out of the crib before the other arrives? Not to mention coordinating childcare, household finances, and time away from work.⁠

So with all of the buzz surrounding the timing between pregnancies, we were curious to dive into the research to learn how it might impact the health and nutrient status of mama and her future pregnancies.

Before we get into the discussion, let’s first look at what happens in your body after a pregnancy - what recovery needs to take place in order to be ready for another pregnancy. 

  1. Restoration of nutrients: Ideally if you’re taking a comprehensive prenatal vitamin, you won’t find yourself terribly depleted, but still, pregnancy is incredibly demanding on the body and it’s likely that following labor and delivery your body will still need to restore key nutrients, especially if a mama is going into her pregnancy already deficient (unfortunately a lot of mamas!) If you’re breastfeeding, your body is still sharing energy and micronutrients with baby through breast milk, and so replenishment of nutrients can take even longer. Remember to continue your prenatal vitamins through this phase!
  2. Pelvic floor recovery: Research shows that it often takes a full year for pelvic floor function to return to baseline - this is the case even if you aren’t experiencing common postpartum symptoms like leaking urine. We suggest all mamas see a pelvic floor physical therapist following birth for a simple evaluation. At the best, your mind will be put at ease that you’re recovering well. At the worst, you’ll get some great tools and exercises to support your recovery.
  3. Balancing of hormones: We aren’t just referring to sex hormones like estrogen, progesterone, and prolactin, but also thyroid and adrenal hormones too. Both are very much impacted by pregnancy, and postpartum thyroid and adrenal problems are common. The balancing of hormones can also impact mama’s mood and emotional wellbeing. 
  4. Reset of the vaginal microbiome: The vaginal microbiome shifts substantially throughout pregnancy and during delivery to protect baby, even if birth is by cesarean section. It is subject to changes in composition of bacteria and pH, as well as infections like bacterial vaginosis. It can take up to a year—for the vaginal microbiome to go back to how it was before pregnancy. We recommend continuing probiotic supplementation even after delivery while this shift takes place. Our Pre/Probiotic is specifically designed to support the microbiome of mama and baby.

These changes are part of a significant physical and emotional shift that happens after giving birth, and they can last far beyond the Fourth Trimester. A pregnancy that follows too quickly may not allow mama’s body to fully recover, which can have implications for both mama and a subsequent baby’s health.

Related Reading: When is too soon to have a baby?

How does it affect mom?

  • Nutrient deficiencies: Deficiencies of certain nutrients, primarily Vitamin B6 and Magnesium can contribute to nausea, particularly in the First Trimester. Deficiencies of nutrients can cause several concerns like anemia with low Iron, decreased bone density with low calcium, compromised immunity and mood concerns with low Vitamin D, brain fog with low Vitamin B12 and low Omega-3s, adrenal dysfunction with low Vitamin C, and compromised dental health. If available to you, we suggest checking levels of key nutrients after weaning and/or before planning a subsequent pregnancy.
  • Thyroid concerns: Pregnancy puts tremendous stress on your thyroid gland as it ramps up production of hormones by more than 50% to support baby’s thyroid and brain development. Underactive thyroid is common in postpartum and can lead to fatigue, difficulty losing weight, difficulty conceiving, and increased risk of miscarriage in subsequent pregnancies. A full thyroid panel is recommended during the Fourth Trimester, as well as prior to conception of a pregnancy.
  • Risk of premature birth: Research has shown that women who got pregnant within a year of giving birth were twice as likely to have that new baby born prematurely, compared with women who waited at least 18 months.
  • Emotional health struggles: hormonal shifts and major life changes and family dynamics can take a toll on mama’s emotional well-being. A narrow gap between babies can intensify some of the struggles around anxiety and mood.

Related Reading: What to know about pregnancy over 35

How does it affect baby?

  • Nutrient deficiencies: If the second baby is in close succession, the mother’s nutrient reserves may be depleted which can increase the risk in the second child of intrauterine growth restriction (IUGR) and adversely affect infant nutrient stores at birth. As DHA is very often depleted in mama, a lack of sufficient DHA during pregnancy and while breastfeeding can also negatively influence an infant’s brain development. The impact can extend to breastfeeding as well, as nutrient deficiencies may also adversely impact the concentration of certain nutrients in breastmilk. Our practitioner community notes that depletion of key minerals like calcium and magnesium, as well as helper nutrients D3 and K2, can result in skeletal abnormalities in baby. This is more common with subsequent pregnancies, as mama's own stores become depleted through pregnancy and breastfeeding without proper supplementation and time for recovery and replenishment. 
  • Risk of premature birth: As noted above, the risk of premature birth increases with a shorter birth interval. Premature birth can impact several organs and systems in an infant that have not fully developed, including the lungs/respiratory system, heart/cardiovascular system, brain/cognitive challenges, digestive difficulties, and compromised immunity. 

Is there an ideal timing?

So if we know that too short an interval between babies can negatively impact both mama and baby, what’s the ideal time frame between pregnancies?

While many resources suggest an 18 month gap between the birth of one baby and conception of another, a systematic review of 34 studies on how birth spacing affects maternal and child nutritional status suggests that this may not be true. Instead of simply time between birth, the research suggests that the nutritional status of a woman and her subsequent children is affected by something called the recuperative interval - the time that a woman is not pregnant or lactating. In other words, not all time between babies is equal. This is because breastfeeding is equally or more nutritionally demanding on a mama’s body than pregnancy, so the longer she nurses the more time she’ll need to replenish nutrients after she finishes. 

That’s not to say that you should wean your first baby too soon just to return to fertility, as that could have implications on your first baby’s health. It’s simply to say that ideally, you’d strike a balance between nursing your first and allowing sufficient time for your body to recover and replenish. 

Emotional readiness vs. physiological readiness

While no scientific literature can determine when you and your family are emotionally ready to welcome a new child into the mix, our aim in presenting the research is to help you optimally achieve physiological readiness.

Only you can determine what is right for your body and family. The goal from a physiological standpoint is simply to attempt to get your body into a state where nutrients are replenished, hormones are balanced, and the body feels physically capable of carrying another baby. Testing of nutrients and thyroid before, during, and after pregnancy can also help to inform your decision.

We hope you feel empowered to know what factors might influence your own nutritional status and that of future babies so that you can plan as much as you want or can. Ultimately, the best thing you can do to optimize the health of you and all of your babies is to make sure that you’re taking good care of your body by getting adequate sleep, minimizing stress, and ensuring proper nutrition through a balanced diet and a comprehensive prenatal vitamin along with Omega-3s and a Probiotic. Practice these routines throughout your entire pregnancy, lactation, and straight through to any subsequent pregnancies. 

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Hillary Bennetts, Nutritionist

Hillary Bennetts is a nutritionist and business consultant focusing on prenatal and postpartum health. In addition to nutrition consulting, she provides business consulting and content creation for companies in the health and wellness industry. Hillary spent almost a decade in corporate consulting before shifting gears to combine her lifelong passion for health and wellness with her business background and nutrition education.