Children of single mothers by choice show favorable birth outcomes

The children of single mothers who conceive through medically assisted reproduction (MAR) have similar outcomes to babies of partnered mothers who had conceived naturally, a UCL-led study has found.

Babies of single-mothers-by-choice were also less likely to have low birth weight or to be born pre-term compared to babies of single mothers who conceived naturally as well as children of partnered mothers who had conceived with MAR techniques such as IVF.

Since the birth of the first IVF baby in 1978, over 10 million children worldwide have been conceived through assisted reproduction techniques. As more women choose to become mothers without a partner and assisted reproduction becomes increasingly accessible, the number of single mothers 'by choice' is steadily growing. Yet we know remarkably little about the health and development of their children." 

Dr. Alina Pelikh, Corresponding Author, UCL Social Research Institute

The study used Finnish population data of over 500,000 first-born babies between 1996 and 2020. On average, MAR was used in 7.8% of the pregnancies. Of this group, 5.4% were conceived while the mother was single, a figure that went from 2.2% in 1996-2000 to 10.2% by 2016-2020. 

The researchers studied several birth outcomes including low birth weight (under 2.5kg) and pre-term birth (less than 37 weeks). They compared the birth outcomes across four groups of women: single women who had used MAR to conceive (0.4%); single women who had conceived spontaneously (6.9%); partnered women who had conceived spontaneously (85.3%); and partnered women who had used MAR to conceive (7.4%).

Before accounting for differences between mothers, babies born to single mothers by choice had slightly poorer average birth outcomes. Once differences in maternal characteristics (such as age, income and education) and if the child was part of a multiple birth (which is more common among MAR births and highly correlated with poorer birth outcomes) were taken into account, the birth outcomes for children of single-mothers-by-choice were largely similar to the outcomes of babies born to partnered mothers who had conceived without MAR. 

Co-author Professor Alice Goisis (UCL Social Research Institute) said: "While single-mothers-by-choice tend to be older than other mums and may experience higher levels of stress during conception and pregnancy, these women typically have higher levels of education, income and have strong fertility intentions – factors which are strongly associated with more favorable birth outcomes.

"Crucially, unlike partnered women who use IVF because they have difficulty conceiving, single-mothers-by-choice are far less likely to have underlying fertility problems that are themselves a known risk factor for adverse birth outcomes, which may partly explain the differences observed."

These findings align with Professor Goisis's research showing that groups who use MAR without fertility problems, such as lesbian couples, have birth outcomes similar to those who conceive without medical intervention.

Dr Pelikh said: "Our findings suggest that although single-mothers-by-choice share some characteristics with other parents, they should be understood as a unique and distinct grouping. 

"Single-mothers-by-choice often have strong fertility intentions, sufficient financial resources, and extensive support networks. While many mothers-to-be use MAR, and many women enter parenthood without a partner, the experience of single-mothers-by-choice should not be generalized. 

"As more and more people delay not just parenthood, but also partnership, single-motherhood-by-choice is likely to become more common. It is crucial that we better understand its impact on children's health outcomes."

This study used Finnish data, a context in which MAR treatment is largely publicly subsidized, resulting in a more diverse population of women accessing these services compared to countries with predominantly private funding.