A two-year-long wait between pregnancies is suggested by the World Health Organization, but is this length of time necessary, and why?
The average age for first-time mothers is on the rise. The average age for first-time mothers ranges between 26 and 29 years of age in Canada and the United States.1,2
According to a 2020 Forbes article,3 most women claimed financial reasons for delaying motherhood. The article stated that in a response to a survey by SoFi and Modern Fertility (online personal finance company and reproductive health company respectively), 60% of the respondents claimed they didn’t have enough money to start a family, while 51% claimed they wanted to be earning a higher salary before having children.3
Time between pregnancies
The World Health Organization in 2005 has suggested a two-year wait (or interpregnancy interval) between the birth of a child and attempting to conceive the next.4
A two-year wait may minimize the potential for preterm births (birth prior to the 37th week), small-for-gestational-age birth, or even low birth weight. These adverse outcomes have been linked to varied interpregnancy intervals.4
Recently an international group looked at the information available on women who have had multiple births over a certain time frame to help shed light on what might be a safe interval between pregnancies.4
The researchers obtained data from four high-income countries (Finland, Norway, Australia, and the United States), going back up to thirty-six years.4
When looking at the data for women who had more than one child, they saw that shorter waits (less than six months) may only result in spontaneous pre-term births, while the longer periods (more than five years) could result in both pre-term births and small for gestational age births. Comparing the data between different women, both short waits (less than a year) and long waits (more than five years) had higher risks for both preterm births and small-for-gestational-age births (when compared to the suggested 18-24 months). 4
It is noted that these studies don’t take into account the health of the mother prior to any of the births, or during the different interpregnancy periods.4
The results of this study suggest that the wait between pregnancies for women in developed countries may not have to be 18-24 months. The study also suggests that longer time periods between pregnancies (3-5 years) may also increase the risk of pre-term births and small-for-gestational-age births.4
There is no definitive answer on how long to wait between pregnancies, there are often many factors to consider. It is important to always follow your doctor’s guidance on what is right for you.
1) Mathews, T., & Hamilton, B. (2016). Mean age of mothers is on the rise: United States, 2000-2014. National Center of Health Statisitcs, Hyattsville, MD.
2) Statistics Canada. (n.d.). Table 13-10-04018-01: Crude birth rate, age-specific fertility rates and total fertility rates (live births). Retrieved 07 22, 2021, from Statistics Canada: https://doi.org/10.25318/1310041801-eng
3) Stahl, A. (2020, 05 01). New Study: Millennial women are delaying having children due to their careers. Retrieved 07 21, 2021, from Forbes.com: https://www.forbes.com/sites/ashleystahl/2020/05/01/new-study-millenial-women-are-delaying-having-children-due-to-their-careers/?sh=6c1135d276a
4) Tessema, G., Marinovich, M., Haberg, S., Gissler, M., Mayo, J., Nassar, N., et al. (2021). Interpregnancy intervals and adverse birth outcomes in high income countries: An international cohort study. PLoS ONE , 16 (7), e0255000.
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