BACKGROUND To investigate the effect of fetal sex on fibroids' growth during pregnancy according to the hCG serum levels METHODS: Observational study conducted from January 2007 to December 2016 on women with ultrasound identification of uterine fibroids who had a pregnancy within 1 year from diagnosis. The fibroids diameter was determined during the pre-pregnancy ultrasound, early first trimester (5-7 weeks), late first trimester (11-13 weeks), second trimester (19-21 weeks), and third trimester (31-33 weeks). The diameter growth was calculated in each interval between two ultrasounds. The hCG serum levels were determined both in early and late first trimester. The correlation between hCG levels and fibroid diameter was evaluated. Obstetric outcomes collected were gestational weeks at birth and the rate of cesarean section. Neonatal outcomes were birthweight and Apgar score at 1 min. RESULTS Eighty-seven of the included women had a male fetus, and 70 had a female fetus. A progressive increase of fibroid diameter was observed from pre-pregnancy to second trimester for both fetal sexes. In third trimester, the mean ± SD fibroid diameter of female fetuses showed a slowdown, while the mean ± SD fibroid diameter of male fetuses continued to grow. Women carrying a female fetus presented a higher fibroid diameter in early first trimester (33.5 ± 13.3 mm vs 27.4 ± 11.0 mm, p < 0.01), late first trimester (40.2 ± 13.9 mm vs 34.6 ± 11.7 mm, p < 0.01), and second trimester (40.5 ± 14.9 mm vs 34.7 ± 10.3 mm, p < 0.01). The hCG serum levels resulted higher in women with a female fetus: 61406 (50554-71760) mU/ml vs 46016 (37160-56744) mU/ml (p < 0.01). A positive correlation between hCG levels and fibroid diameter was found both for male and female fetuses (male r = 0.77, 95% CI 0.71-0.82, p < 0.01 and female r = 0.82, 95% CI 0.76-0.86, p < 0.01). CONCLUSION Women with female fetus seem to have a higher growth of fibroids up to second trimester of pregnancy. This process may be mediated by the higher serum hCG levels found in women expecting a female fetus.

中文翻译：

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根据胎儿性别比较子宫肌瘤在怀孕期间的生长方式：一项观察性研究。

背景：根据hCG血清水平调查胎儿性别对妊娠期间肌瘤生长的影响。方法：从2007年1月至2016年12月，对超声诊断子宫肌瘤的妇女进行诊断研究，该妇女在诊断后1年内就已怀孕。肌瘤直径是在孕前超声，孕早期（5-7周），孕晚期（11-13周），孕中期（19-21周）和孕晚期（31-33周）期间确定的。在两次超声之间的每个间隔中计算直径增长。在头三个月的早期和晚期测定hCG血清水平。评估了hCG水平与肌瘤直径之间的相关性。收集的产科结果是出生时的孕周数和剖宫产率。新生儿结局为出生体重和1分钟时Apgar评分。结果纳入研究的女性中有87名具有男性胎儿，而70名具有女性胎儿。从孕前到妊娠中期，两种胎儿性别的肌瘤直径都逐渐增加。妊娠中期，女性胎儿的平均±SD肌瘤直径呈减慢趋势，而男性胎儿的平均±SD肌瘤直径持续增长。携带雌性胎儿的女性在上孕早期（33.5±13.3 mm vs 27.4±11.0 mm，p <0.01），孕早期晚期（40.2±13.9 mm vs 34.6±11.7 mm，p <0.01）和较高的肌瘤直径孕中期（40.5±14.9 mm和34.7±10.3 mm，p <0.01）。具有女性胎儿的女性的hCG血清水平更高：61406（50554-71760）mU / ml与46016（37160-56744）mU / ml（p <0.01）。男性和女性胎儿的hCG水平与肌瘤直径呈正相关（男性r = 0.77，95％CI 0.71-0.82，p <0.01和女性r = 0.82，95％CI 0.76-0.86，p <0.01） 。结论胎儿女性在妊娠中晚期似乎有较高的肌瘤生长。该过程可能由预期有女性胎儿的女性中较高的血清hCG水平介导。