Finnish register study links assisted reproduction in single mothers by choice to comparable birth outcomes

A nationwide Finnish register study found that babies conceived through medically assisted reproduction by women who were single by choice had birth outcomes largely similar to babies conceived naturally by partnered mothers, after differences in maternal characteristics and multiple birth were taken into account. The observational analysis also found that these babies were less likely to have low birth weight or to be born preterm than babies conceived by single mothers who conceived spontaneously and babies conceived through assisted reproduction by partnered mothers. The results do not show that assisted reproduction caused the outcomes, but they indicate that the combination of single motherhood by choice and assisted conception was not associated with poorer average birth outcomes in the population studied.

The researchers analyzed Finnish population records covering more than 500,000 first-born babies born between 1996 and 2020. Medically assisted reproduction, abbreviated MAR in the study, was used in an average of 7.8% of the pregnancies represented in the data. The analysis examined routinely recorded outcomes, including low birth weight, defined as less than 2.5 kilograms, and preterm birth, defined as birth before 37 completed weeks of pregnancy. The peer-reviewed observational study, “Birth outcomes in single motherhood ‘by choice’: A register study of children conceived through medically assisted reproduction,” was scheduled for publication in the International Journal of Epidemiology on 23 September 2026.

The study population was divided into four groups according to the mother’s partnership status at conception and whether conception occurred spontaneously or with MAR. Babies born to single women who used MAR accounted for 0.4% of the cohort. Babies born to single women who conceived spontaneously accounted for 6.9%, babies born to partnered women who conceived spontaneously represented 85.3%, and babies born to partnered mothers who used MAR represented 7.4%. This structure allowed the researchers to compare partnership status and the use of assisted reproduction within the same register-based analysis.

Before adjustment for differences between mothers, babies born to single mothers by choice had slightly poorer average birth outcomes. After the researchers accounted for maternal characteristics, including age, income and education, and for whether the child was part of a multiple birth, the difference was no longer evident. The adjusted outcomes for children of single mothers by choice were largely similar to those recorded for babies born to partnered mothers who conceived without MAR. The study therefore reported a different pattern before and after adjustment, with the unadjusted comparison showing modestly poorer average outcomes and the adjusted comparison showing broadly similar outcomes to the naturally conceived babies of partnered mothers.

Single mothers by choice who used MAR also had lower risks of the two outcomes examined than babies born to single mothers who conceived spontaneously and babies born to partnered mothers who conceived through MAR, including IVF. The release did not provide numerical effect estimates for these comparisons, so the result is best understood in the terms reported: the adjusted outcomes were largely similar across groups, while babies of single mothers by choice who used MAR were less likely to experience low birth weight or preterm birth than the two comparison groups described. The findings do not show a uniform disadvantage associated with either assisted reproduction or unpartnered motherhood; the observed pattern differed according to the groups being compared.

Multiple birth was one factor considered in the analysis. MAR births were more likely to involve multiple births, and multiple birth was strongly correlated with poorer birth outcomes. By accounting for this feature, as well as differences in maternal age, income and education, the researchers made a more comparable assessment across the four groups. The analysis did not establish that any one of these factors caused the overall pattern, but it showed that the raw group differences were substantially reduced after the specified maternal and birth characteristics were taken into account.

Corresponding author Dr Alina Pelikh said the study addresses a group about which relatively little was known: “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.” The study used a large population-based register rather than reporting results from a small clinical sample.

Co-author Professor Alice Goisis said the mothers included in the single-mothers-by-choice group tended to be older than other mothers and might experience higher levels of stress during conception and pregnancy. At the same time, they typically had higher levels of education and income, along with strong fertility intentions, factors the release described as strongly associated with more favorable birth outcomes. She also emphasized a distinction between women who use IVF because they have difficulty conceiving and single mothers by choice, who are less likely to have underlying fertility problems that are themselves a known risk factor for adverse birth outcomes. The authors said this difference may partly explain the observed results.

The share of MAR pregnancies involving a mother who was single increased during the study period. Among MAR pregnancies, the proportion conceived while the mother was single rose from 2.2% in 1996–2000 to 10.2% in 2016–2020. The authors linked this shift to changes in family formation, including more women delaying both partnership and parenthood, and to assisted reproduction becoming increasingly accessible. The findings also align with earlier work by Goisis showing comparable birth outcomes among groups using MAR without fertility problems, such as lesbian couples, and babies conceived without medical intervention.

The findings come from Finland, where MAR treatment is largely publicly subsidized, resulting in a more diverse population of women accessing these services than in countries where treatment is predominantly privately funded. The observational design also limits what can be concluded: the study assessed birth outcomes rather than children’s later health or development, and it did not establish that the use of MAR itself produced the similarities or differences among groups. Taken together, the data support a specific conclusion for the Finnish register studied: among more than 500,000 first-born babies, those born to single mothers by choice using MAR had broadly comparable adjusted birth outcomes to babies of partnered mothers who conceived naturally. The authors said it is important to understand this distinct group as more women become parents without a partner and use assisted reproduction to conceive.

Subject of Research: Birth outcomes among children conceived through assisted reproduction by single mothers by choice

Article Title: Babies born to single mothers by choice have birth outcomes comparable to average

Article References: Babies born to single mothers by choice have birth outcomes comparable to average. Original publication (Bibliographic details unavailable.)

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Keywords: assisted reproduction, single motherhood by choice, birth outcomes, preterm birth, low birth weight, IVF, Finland, register study, observational research, Babies, born, single