Model Inputs \(\rightarrow\) Biological Parameters \(\rightarrow\) Month of Delivery


This parameter refers to the gestational age at delivery (in months).


Data are based on the fetal lifetable by Goldhaber and Fireman (1991).[1] Estimates of live births from Table 2 were converted into cumulative probabilities of birth by gestational month:

Gestational Month Cumulative Prob. Of Delivery
2 0
3 0
4 0
5 0.0005
6 0.0018
7 0.0044
8 0.0263
9 0.5999
10 1.0


For simplicity, we do not explore any uncertainty surrounding this parameter and assume that the probabilities are fixed.

Model Implementation

If a pregnancy is simulated to end in a delivery (i.e. live birth or stillbirth), the month of delivery is drawn from the table of probabilities. We currently do not differentiate between delivery times for singleton and twins, although twins are generally born earlier.


  1. Goldhaber MK, Fireman BH. The fetal life table revisited: spontaneous abortion rates in three Kaiser Permanente cohorts. Epidemiology 1991; 2: 33-39. PMID: https://www.ncbi.nlm.nih.gov/pubmed/2021664

GMatH (Global Maternal Health) Model - Last updated: 28 November 2022

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