Saving Lives With Better Gestational Age Estimation: Improving the Accuracy of Recall and Reporting of the Date of Last Menstrual Period (LMP) in Rural Bangladesh

Background:

Bangladesh has a high maternal (194 per 100,000 live births) and newborn mortality (28 per 1000 live births)(1-3). In 2010, prematurity represented ~14% of all births and directly and indirectly contributed to 45% of all neonatal deaths(4, 5). Accurate estimation of gestational age (GA) is a critical for providing optimal clinical care during the prenatal, delivery and postnatal period and for public health interventions(6). Knowing GA to the week is essential for determining the adequacy of fetal growth, correct diagnosis of preterm or post-term labor and also for the correct use of many interventions (e.g., antenatal corticosteroids therapy, tocolytics, continuous positive airway pressure) targeted to improve maternal and newborn outcomes(7).

Three methods of GA estimation are primarily used - menstrual based dating (LMP), ultrasonography (USG) and neonatal assessment, all of which have some strengths and weaknesses(8). USG, based on biometric measurements of the fetus, is considered to be the gold standard when done before 20 weeks of gestation i.e., when biologic variations in fetal size and the effects of growth restriction are low(9). However, the accuracy of USG decreases when done in the latter trimesters, particularly in settings with high intrauterine growth restriction, as in Bangladesh(10). However, USG is often unavailable in low-resource countries, especially in rural areas. Even if it is available, the equipment can be of poor quality and operated by personnel with minimal expertise(10). In addition, pregnancies are often not identified until the 2nd or 3rd trimesters and women often seek antenatal care late in their pregnancies, which further limits the use of USG to assess GA(10-12).

Alternate methods of assessing GA are therefore preferred in such settings. One approach is to use neonatal assessments that are based on standardized scoring systems of physical and neuromuscular maturity. These are, however, less precise then obstetric estimates and also require skilled personnel which is frequently not practical(13). Dating based on the LMP is another alternative. It is a simple, low-cost method recommended by the World Health Organization(14). However, several studies have shown that that approximately 15-45% of pregnant women are unable to recall their LMP accurately resulting in an unreliable estimate and digit preference(15-17). Recall period is crucial determinant influencing accuracy of LMP. Literature suggests that LMP recall is more precise with shorter recall period.(15) Accuracy in recall of LMP is also limited due to irregularity or individual variations in the length of the menstrual cycle, short birth spacing, preconception amenorrhea and implantation bleeding(18, 19). This is further complicated by late presentation for first antenatal care consultation and providers with minimal skills in probing for an accurate LMP date. Reliance on LMP alone has shown a tendency to overestimate GA at the extremes of gestation which is more common in women with no or low education and those living in poverty(15, 20). Despite the limitations, studies conducted in Bangladesh and Guatemala has suggested LMP to be the preferred method for determining GA in low-resource settings(10, 21).

The study therefore aim to determine the efficacy of three interventions targeted to improve the recall and reporting of the LMP among women in rural Bangladesh. The interventions include both conventional LMP dating calendar as well as an innovative e-platform - mobile phones and smart phone applications.