Bassey O O
Br J Obstet Gynaecol. 1977 Jun;84(6):439-43. doi: 10.1111/j.1471-0528.1977.tb12619.x.
A study by questionnaire of the incidence of pregnancy heartburn in two groups of Nigerians and one group of Caucasians showed an incidence of 9-8 per cent in all Nigerians as against 78-8 per cent in Caucasians. The difference was highly significant (chi 2 = 102-75; P less than 0-0001). An oesophageal manometric study of the lower esophageal sphincter in 12 non-pregnant women and in 12 pregnant Nigerians (10 without heartburn and 2 with heartburn) showed that the mean lower oesophageal sphincter pressure (+/- SD) in the pregnant patients without heartburn was 20-1 +/- 7-0 mm Hg as against 17-9 +/- 7-0 in the non-pregnant women. While one pregnant subject without heartburn had a lower oesophageal sphincter which was partially displaced into the thorax, none of the non-pregnant women had such sphincter displacement. The two pregnant women with heartburn had low resting sphincter pressures and in both of them the sphincters were partially in the thorax. It is argued that pregnancy heartburn is due to the displacement of the lower oesophageal sphincter into the negative pressure environment of the thorax where the sphincter is less capable of resisting reflux. It is also argued that pregnancy heartburn is commoner in Caucasians that in Nigerians because the spincter in non-pregnant Caucasians is often partly intrathoracic and is thus more easily displaced completely into the thorax by the pregnant uterus.
一项通过问卷调查对两组尼日利亚人和一组高加索人妊娠烧心发病率的研究表明，所有尼日利亚人的发病率为9 - 8%，而高加索人的发病率为78 - 8%。差异具有高度显著性（卡方 = 102 - 75；P小于0 - 0001）。对12名未怀孕女性和12名怀孕尼日利亚女性（10名无烧心症状，2名有烧心症状）的食管下括约肌进行食管测压研究显示，无烧心症状的怀孕患者食管下括约肌平均压力（±标准差）为20 - 1±7 - 0毫米汞柱，而未怀孕女性为17 - 9±7 - 0毫米汞柱。虽然一名无烧心症状的怀孕受试者食管下括约肌部分移位至胸腔，但未怀孕女性均无此类括约肌移位情况。两名有烧心症状的怀孕女性静息时括约肌压力较低，且两人的括约肌均部分位于胸腔内。有人认为妊娠烧心是由于食管下括约肌移位至胸腔的负压环境中，在该环境中括约肌抵抗反流的能力较弱。还有人认为妊娠烧心在高加索人中比在尼日利亚人中更常见，因为未怀孕高加索人的括约肌常部分位于胸腔内，因此更容易被怀孕的子宫完全移位至胸腔。
