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  • Writer's pictureRebecca Genuis

Having kids close together

In the medical world, we sometimes talk about an ideal "interconception interval"- referring to the amount of time between when mom gives birth to one child and conceives her next child. It's thought that having an interval of 18-24 months is best to optimize the health of mom and her next child.

Indeed, it's been found that shorter intervals result in higher rates of preterm births, low birth weight babies and pre-eclampsia.

I've sometimes wondered about why this is. Having children close together doesn't guarantee that a mother/child will run in to these problems but it increases the risk. Why is it true of some, but not of all?

I wonder if the answer may lie in looking at a woman's nutritional status. We know that pregnancy, and lactation, can both be very demanding on a woman's body. The child will take what he or she needs from mum, even if that means mum ends up deficient or somewhat depleted.

For example, let's consider omega 3 levels throughout pregnancy and the postpartum period. It's been found that it's generally in the third trimester that the mother's levels will begin to decline significantly from her baseline, likely because this is when substantial brain development is happening in the baby. But after this decline, there's no guarantee her levels will return to their baseline. If she is breastfeeding her baby, she will continue to pass along these important fatty acids to her babe, and if she's not intentional about restocking herself, she likely won't. Population studies have found that a mom's level of docosahexanoic acid (DHA, an omega 3) in later pregnancies is generally significantly lower than what it is in her first pregnancy! And given that we know lower levels of DHA are associated with preterm labour (in addition to many many other concerns), perhaps this is one piece of the puzzle explaining why a shorter interconception interval may have adverse outcomes.

The good news is that if you are someone who would like to have lots of children and have them closer together, this isn't something that is insurmountable. By paying careful attention to your diet, and perhaps select supplements, you can carefully work to re-establish your nutritional status, even in a short period of time, to optimize the health of your future children.

Nutrients are the building blocks of our health and our children, and pregnancy and lactation are very demanding in this respect. If women are aware of the amount of "giving" their body is doing during their reproductive years, they can also start to pay attention to restocking themselves, and thus contribute to their, and their children's good health.


Conde-Agudelo A, Rosas-Bermudez A, Kafury-Goeta AC. Birth spacing and risk of adverse perinatal outcomes: a meta analysis. JAMA. 2006;295:1809–1823.

Conde-Agudelo A, Rosas-Bermudez A, Castaño F, Norton MH. Effects of birth spacing on maternal, perinatal, infant, and child health: a systematic review of causal mechanisms. Stud Fam Plan. 2012;43:93–114.

Khoshnood B, Lee KS, Wall S, Hsieh HL, Mittendorf R. Short interpregnancy intervals and the risk of adverse birth outcomes among five racial/ethnic groups in the United States. Am J Epidemiol. 1998;148:798–805.

Klerman LV, Cliver SP, Goldenberg RL. The impact of short interpregnancy intervals on pregnancy outcomes in a low-income population. Am J Public Health. 1998;88:1182–1185.

Morse, N. (2012). Benefits of Docosahexaenoic Acid, Folic Acid, Vitamin D and Iodine on Foetal and Infant Brain Development and Function Following Maternal Supplementation during Pregnancy and Lactation. Nutrients, 4(12), pp.799-840.

Zhu BP, Rolfs RT, Nangle BE, Horan JM. Effect of the interval between pregnancies on perinatal outcomes. N Engl J Med. 1999;340:589–594.

1 Comment

May 11, 2021

Well said. I had six children in eight years and took liquid cod liver oil and vitamin D each time (as per Dr. Stephen Genuis' orders). I exercised and ate fairly well, not perfect, but all my babies were healthy and full term. Sadly I had one early miscarriage (blighted ovum). fter my third baby I started taking desiccated thyroid. It was taxing on my body to have a baby every 18-23 months but overall I felt great and loved it!

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