Fertilization in Vitro

A literature search in PUBMED was done covering 1 January 1995 to 12 September 2012 with the key terms maternal anthropometry and pregnancy (only human studies in English were selected with an abstract and/or full text). The year 1995 was chosen as a start as it was the year that the WHO Collaborative study on maternal anthropometry and pregnancy outcomes was published, and it is regarded as a milestone publication on this topic13
^,14 . The search provided 6,697 records which were subsequently narrowed down to 4,000 records when publications were filtered excluding studies with specific drugs or hormones, diseases, environmental exposure, substance abuse, triplets, twins, in-vitro fertilisation, obesity, cigarette smoking, and anaemia. The search was further limited to studies that reported on one or more of the selected anthropometric indicators (MUAC, BMI, maternal weight and/or weight gain and/or height), that provided statistical tests such as odds ratio (OR) or relative risk (RR) and on LBW, PTB or IUGR. The search provided 310 records, and 11 referred to the context in developing countries (as defined by the World Bank (http://data.worldbank.org/about/country-classifications/country-and-lending-groups; accessed 4 October 2012)). Additionally, four more relevant studies were found when reference lists of selected studies were examined.

Preterm birth was the primary outcome of this study, which was defined as births before 37 completed weeks of gestation. The World Health Organization (WHO) further subdivided preterm birth based on gestational age: extremely preterm (< 28 weeks), very preterm (28 to < 32 weeks), and moderate or late preterm (32 to < 37 weeks) [23 (link)]. Secondary outcomes were NICU admission, low birthweight and small for gestational age. Low birthweight was defined as a birthweight < 2500 g, and small for gestational age was defined as a birthweight less than the 10th percentile. The following variables were collected: maternal age at delivery (years), race [Asian, Black (Black or African American), White, other (American Indian or Alaska Native, Native Hawaiian or Other Pacific Islander, and more than one race)], education [less than 12 grade, high school/general educational development (GED), some college or associate degree (AA), bachelor or higher], pre-pregnancy weight (lb), pre-pregnancy body mass index (BMI) (BMI < 18.5 kg/m², underweight; BMI = 18.5–24.9 kg/m², normal; BMI = 25.0–29.9 kg/m², overweight; BMI = 30.0–34.9 kg/m², obesity), delivery weight (lb), weight gain (lb), smoking before pregnancy (yes or no), smoking status 1st/2nd/3rd trimester (mother-reported smoking in the three trimesters of pregnancy, yes or no), hypertension eclampsia (yes or no), gestational hypertension (yes or no), pre-pregnancy hypertension (yes or no), number of prenatal visits, the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC, receipt of WIC food for the mother during this pregnancy, yes or no), plurality, prior birth now living, prior birth now dead, prior other terminations, total birth order, gestational age (weeks), newborn sex (female or male), birth weight (g), infertility treatment used (yes or no), pregnancy method (natural pregnancy, pregnancy via ART), method of delivery [spontaneous, non-spontaneous (forceps, vacuum, cesarean)], preterm birth [extremely preterm, very preterm, moderate or late preterm; spontaneous, indicated (forceps, vacuum, cesarean)], NICU admission, low birthweight (yes or no), and small for gestational age (yes or no). WIC is a program intended to help low income pregnant women, infants, and children through age 5 receive proper nutrition by providing vouchers for food, nutrition counseling, health care screenings and referrals; it is administered by the U.S. Department of Agriculture (https://ftp.cdc.gov/pub/Health_Statistics/NCHS/Dataset_Documentation/DVS/natality/UserGuide2019-508.pdf). Infertility treatment referred to using fertility enhancing drugs, artificial insemination, intrauterine insemination, or using ART. ART included in vitro fertilization (IVF), gamete intrafallopian transfer (GIFT), and zygote intrafallopian transfer (ZIFT). Information on variables is available at https://www.cdc.gov/nchs/nvss/index.htm.

This was a retrospective cohort study, in which the in vitro fertilization (IVF) was performed from January 2018 to December 2020 in the Center for Assisted Reproductive Technology of Northwest Women’s and Children’s Hospital (Xi’an, China). The protocol of the study was approved by the institutional review board of the hospital. Data were extracted from electronic medical records. Patients who underwent FET and achieved ongoing pregnancy were enrolled. Ongoing pregnancy was defined as the presence of at least one fetal heart pulsation on ultrasound beyond 20 weeks. All patients were enrolled only once. Women with chronic hypertension before pregnancy were excluded. Written informed consent was obtained from the participants before treatment.

A total of 68 animals were divided into two groups of 34 animals each, with 4–6 animals per cage. The control group was administered a drug vehicle (saline). The VPA group was administered 200 mg/kg VPA. VPA and saline were administered daily via intraperitoneal injection to mice for 4 weeks from 6 to 10 weeks of age. The timing of this administration was determined based on the chemical effects that occurred before sexual maturity and epigenomic effects after maturity [23 (link), 24 (link)]. Two weeks after the final dose, 38 animals were sacrificed at 12 weeks of age and used for in vitro fertilization and sperm DNA methylation analysis. This 2-week rest period facilitates the drug-affected sperm to reach the cauda epididymis and eliminates the acute effects of drug administration, enabling chronic effects to be studied. For western blot analysis, 18 animals were sacrificed 0, 3, and 7 days after the final dose. To obtain F1 offspring, 12 mice at 12 weeks of age from each group were mated with untreated, virgin, 12-week-old C57BL/6N female mice. Mating was carried out by keeping two female mice for each male mouse in the same cage. Successful mating was confirmed by the presence of sperm plugs. The resulting pups were raised to 12 weeks of age and then subjected to behavioral tests and brain RNA-seq analysis. The F1 offspring used for the behavioral experiments were individually kept from 4 weeks of age to prevent hierarchy in the home cage from affecting behavior.