Deputy Nicholas P, Nguyen Phuong H, Pham Hoa, Nguyen Son, Neufeld Lynnette, Martorell Reynaldo, Ramakrishnan Usha
Nutrition and Health Sciences Program, Laney Graduate School, Emory University, Atlanta, GA, USA.
Thai Nguyen University of Pharmacy and Medicine, Thai Nguyen, Vietnam.
BMC Pregnancy Childbirth. 2017 Jan 11;17(1):25. doi: 10.1186/s12884-016-1192-5.
Accurate estimation of gestational age is important for both clinical and public health purposes. Estimates of gestational age using fetal ultrasound measurements are considered most accurate but are frequently unavailable in low- and middle-income countries. The objective of this study was to assess the validity of last menstrual period and Farr neonatal examination estimates of gestational age, compared to ultrasound estimates, in a large cohort of women in Vietnam.
Data for this analysis come from a randomized, placebo-controlled micronutrient supplementation trial in Vietnam. We analyzed 912 women with ultrasound and prospectively-collected last menstrual period estimates of gestational age and 685 women with ultrasound and Farr estimates of gestational age. We used the Wilcoxon signed rank sum test to assess differences in gestational age estimated by last menstrual period or Farr examination compared to ultrasound and computed the intraclass correlation coefficient (ICC) and concordance correlation coefficient (CCC) to quantify agreement between methods. We computed the Kappa coefficient (κ) to quantify agreement in preterm, term and post-term classification.
The median gestational age estimated by ultrasound was 273.9 days. Gestational age was slightly overestimated by last menstrual period (median 276.0 days, P < 0.001) and more greatly overestimated by Farr examination (median 286.7 days, P < 0.001). Gestational age estimates by last menstrual period and ultrasound were moderately correlated (ICC = 0.78) and concordant (CCC = 0.63), whereas gestational age estimates by Farr examination and ultrasound were weakly correlated (ICC = 0.26) and concordant (CCC = 0.05). Last menstrual period and ultrasound estimates of gestational age were within ± 14 days for 88.4% of women; Farr and ultrasound estimates were within ± 14 days for 55.8% of women. Last menstrual period and ultrasound estimates of gestational age had higher agreement in term classification (κ = 0.41) than Farr and ultrasound (κ = 0.05).
In this study of women in Vietnam, we found last menstrual period provided a more accurate estimate of gestational age than the Farr examination when compared to ultrasound. These findings provide useful information about the utility and accuracy of different methods to estimate gestational age and suggest last menstrual period may be preferred over Farr examination in settings where ultrasound is unavailable.
The trial was registered at ClinicalTrials.Gov as NCT01665378 on August 13, 2012.
准确估计孕周对临床和公共卫生目的均很重要。使用胎儿超声测量来估计孕周被认为是最准确的，但在低收入和中等收入国家却常常无法实现。本研究的目的是在越南的一大群女性中，评估末次月经和法尔新生儿检查估计的孕周与超声估计相比的有效性。
本分析的数据来自越南一项随机、安慰剂对照的微量营养素补充试验。我们分析了912名有超声检查且前瞻性收集了末次月经孕周估计值的女性，以及685名有超声检查且有法尔孕周估计值的女性。我们使用Wilcoxon符号秩和检验来评估末次月经或法尔检查估计的孕周与超声估计的孕周之间的差异，并计算组内相关系数（ICC）和一致性相关系数（CCC）以量化不同方法之间的一致性。我们计算卡帕系数（κ）以量化早产、足月和过期产分类中的一致性。
超声估计的孕周中位数为273.9天。末次月经略微高估了孕周（中位数276.0天，P＜0.001），而法尔检查则高估得更多（中位数286.7天，P＜0.001）。末次月经和超声估计的孕周中度相关（ICC = 0.78）且一致（CCC = 0.63），而法尔检查和超声估计的孕周弱相关（ICC = 0.26）且一致（CCC = 0.05）。末次月经和超声估计的孕周在88.4%的女性中在±14天内；法尔和超声估计在55.8%的女性中在±14天内。末次月经和超声估计的孕周在足月分类中的一致性（κ = 0.41）高于法尔和超声（κ = 0.05）。
在这项针对越南女性的研究中，我们发现与超声相比，末次月经提供的孕周估计比法尔检查更准确。这些发现提供了有关不同孕周估计方法的效用和准确性的有用信息，并表明在无法进行超声检查的情况下，末次月经可能比法尔检查更可取。
该试验于2012年8月13日在ClinicalTrials.Gov上注册，注册号为NCT01665378。
