Examining outcomes beyond 20 weeks gestational age in pregnancies conceived by ART compared to spontaneously conceived pregnancies

1. To determine if a difference in outcomes for pregnancies beyond 20 weeks gestational age exists between ART-treated and spontaneous conception populations in BC. Specifically, the investigators will examine the prevalence for gestational diabetes, gestational hypertension, premature deliveries, low birth weight, miscarriages, maternal length of stay in hospital, NICU admissions, APGAR scores<6, and arterial cord gas pH<7.
2. To examine the trend of outcomes beyond 20 weeks GA associated with ART by calendar year from March 2008 to April 2018.

The research literature from other study populations suggest the prevalence of pregnancy complications are higher amongst women with ART-treated deliveries. Specifically, there is a trend towards higher rates of gestational diabetes, pregnancy induced hypertension, premature deliveries, low birthweight deliveries, perinatal deaths and maternal length of stay in hospital after delivery. The challenge lies in determining the degree of difference and the trend.

Given the relatively older age of conception in BC, the investigators hypothesize that the aforementioned complications may in fact be higher in both the spontaneous conception and ART-treated groups. That being said, the investigators suspect the ART group is likely to still have a higher rates of gestational diabetes, hypertension, premature deliveries, low birthweight, and miscarriages.

The investigators intend to conduct a retrospective cohort study examining differences in pregnancy outcomes after 20 weeks GA in ART-treated versus fertile women.

The study population will consist of women in BC with in-province deliveries occurring between March 1 2008 and April 31 2018 that resulted in singleton live birth or fetal death at >20 weeks. Only fertile women conceiving their index pregnancy by assisted reproductive technology (ART) will be included. Multiparous women and women with multiple gestation deliveries will be excluded. Also, any women missing data including gravida, parity, age, date of birth, neonatal birth weight, neonatal APGARs, neonatal live birth versus stillbirth Data will be collected from the perinatal services BC database, following approval. A biostatistician will be employed to help utilize the data requested.

Obstetric and Fetal outcome measures of prematurity (<37 weeks GA), low birthweight (<2500g), small for gestational age (in live births), perinatal death (fetal death >20 weeks to death of newborn up to 7 days post-delivery), prolonged maternal length of stay in hospital following delivery (>3 days), and maternal hospital readmission (rehospitalization 0-60 days after delivery plus emergency department of observation stay visits 0-7 days after delivery), gestational diabetes (insulin and non-insulin dependent), gestational hypertension (>140/90 after 20 weeks GA), pre-eclampsia HELLP Syndrome, Postpartum infection, admission to NICU, APGAR score <6, cord arterial gas pH <7. Chi square statistics will be used to evaluate statistical differences in binary outcomes among fertile and ART-treated groups while ANOVA tests will be implemented to evaluate differences in continuous outcomes. Multivariable models will be adjusted for potential confounders including maternal age (30, 31-34, 35-37, 38-40, >40), smoking (yes/no), chronic hypertension (yes/no), pre-pregnancy diabetes (type 1 and type 2), pre-pregnancy BMI equal to or greater than 30.

Inclusion Criteria:

• Women in BC with in-province deliveries occurring between March 1 2008 and April 31 2018 that resulted in singleton live birth or fetal death at >20 weeks
• Only fertile and women conceiving their index pregnancy by assisted reproductive technology (ART) will be included.

Exclusion Criteria:

• Multiparous women and women with multiple gestation deliveries will be excluded
• any women missing data including gravida, parity, age, date of birth, neonatal birth weight, neonatal APGARs, neonatal live birth versus stillbirth will be excluded

Women in BC with in-province deliveries (following naturally conceived or assisted reproductive technologies) occurring between March 1 2008 and April 31 2018 that resulted in singleton live birth or fetal death at >20 weeks.