Becoming a mother at an advanced age : pregnancy, outcomes, psychological distress, experience of childbirth and satisfaction with life

Abstract

The objectives of this thesis were to investigate adverse pregnancy outcomes, and pregnancy and psychological experiences in women who become mothers in the later phase of the reproductive period. The age of first-time mothers has increased in most high-income countries in recent decades. Research into the postponement of childbirth phenomenon has predominantly focused on pregnancy and infant outcomes, and only to a lesser degree on psychological aspects of postponement.

Study I is a population-based register study including 955 804 primiparous women from the Swedish and Norwegian Medical Birth Registers who gave birth between 1990-2010. It investigates the risk for preterm birth, infants small for gestation age, low Apgar score, stillbirth and neonatal death in women aged 30-34 years, 35-39 years and ≥40 years compared with women aged 25-29 years. Study I also compares risks associated with advanced maternal age with those associated with smoking and being overweight or obese. The adjusted Odds Ratios (aOR) of all outcomes increased with maternal age in a similar way in Sweden and Norway and the risk of fetal death already at age 30-35 years (Sweden OR 1.24; 95% CI 1.13-1.37, Norway aOR 1.26; 95% CI 1.12-1.41). The Swedish data showed that a maternal age of ≥30 years was associated with the same number of additional cases of fetal deaths as being overweight/obesity (251) and a larger number than smoking (67) compared with normal weight, nonsmokers aged 25-29 years, and estimated over the entire time period. Studies II-IV are longitudinal prospective population-based cohort studies based on data from the National Norwegian Mother and Child Cohort Study conducted by the Norwegian Institute of Public Health.

Study II investigated psychological distress in 19 291nulliparous women from mid pregnancy to 18 months after the birth, comparing women of ≥32 years with those of 25-31 years. It was found that women in the oldest group had a slightly increased risk of psychological distress during pregnancy and the first 18 months of motherhood.

Study III investigated 30 065 women’s experience of childbirth at six months postpartum in relation to antenatal expectations, using the same age categories as in Study II. The oldest women had a marginally higher risk of experiencing childbirth as worse than expected. Older women seemed to manage better than younger women when having an operative delivery.

Study IV investigated 18 565 women’s satisfaction with life during pregnancy and the first three years of motherhood, comparing women of 32-37 years and ≥38 years respectively with the same reference groups as above. Women in the two oldest age groups reported a slightly lower degree of satisfaction with life, and the age effect was greatest three years after the birth.

In conclusion, this thesis shows that the postponement of childbirth in high-income countries may increase the risk of adverse pregnancy outcomes at an earlier age than has previously been reported, and that it may have marginal negative effects on women’s emotional wellbeing and satisfaction with life. These findings should be included when giving reproductive health information to young people.