Abdominal skin subcutaneous fat thickness over the gestational period in Korean pregnant women: a descriptive observational study

Purpose: Although insulin is usually injected into the abdominal subcutaneous fat, in pregnancy women tend to avoid abdominal injections due to concern about fetal damage. Prior studies have been limited to only measuring skin-subcutaneous fat thickness (S-ScFT) at one site at specific pregnancy points. This study aimed to measure S-ScFT across several abdominal sites and over the gestational period in Korean pregnant women. This can identify which site would be relatively safe for subcutaneous injection during pregnancy. Methods: Healthy women over 24 weeks of pregnancy in Korea were invited to voluntarily participate in this descriptive study. For the 142 women, S-ScFT of 12 sites in the abdomen were measured by ultrasound, several times over the pregnancy. Each incidence was treated as a case and a total of 262 cases were analyzed.Results: The mean S-ScFT during pregnancy was 1.14±0.47 cm (1.25±0.54 cm at 24+0–27+6 weeks; 1.17±0.48 cm at 28+0–31+6 weeks; 1.09+0.40 cm at 32+0–35+6 weeks; and 1.06±0.47 cm at 36+0–40 weeks of pregnancy). Most S-ScFT were thicker than 10 mm. But S-ScFTs in the lateral abdomen and some sites were suboptimal (<6 mm), especially in the pre-pregnancy underweight body mass index group, who had a high rate of suboptimal thickness (27.1% overall and 33.9% in the lateral side). Conclusion: The whole abdomen seems to be appropriate for subcutaneous injection in most pregnant Korean women, with a 4 to 5-mm short needle. However, for the lateral abdomen, making the skin fold might be needed for fetal safety.