Table 1

Description of the variables used to examine the risk factors for stillbirth

Risk factors	Description of the variables
Proximal or biodemographic factors
Fetal factors
Sex	Sex of the fetus was coded as either female or male.
Multiple pregnancy	Number of fetuses: Women were categorised as singleton (one fetus) or multiple pregnancy (twins or higher-order multiple gestations).
Maternal factors
Maternal age	Maternal age at the time of the survey was divided into 5-year age bands: <20, 20–24, 25–29, 30–34, 35–39, 40–44, 45 and above.
Gravidity	Gravidity (number of pregnancies) was used as a proxy for parity (number of deliveries) for which information was not available. Gravidity was categorised as ‘first’ if the index pregnancy was the first pregnancy, ‘second - fourth’ and ‘five or more’.
Any complication during pregnancy	Women who reported to have any of the following complications during their index pregnancy were coded as ‘yes’, otherwise ‘no’: anaemia, eclampsia, other hypertensive disorders, antepartum haemorrhage, intrapartum haemorrhage, abnormal fetal position, breech presentation and obstructed labour.
Mode of delivery	This was categorised into vaginal delivery, assisted vaginal delivery and caesarean section.
Intermediate factors or behavioural factors
Lifestyle factors
Smoking tobacco	Women were asked about smoking and chewing tobacco during the interview; current practice was coded as ‘yes’, while women who never practised or no longer practised were coded as ‘no’.
Chewing tobacco
Health seeking behaviour
Antenatal care visits	Number of antenatal care (ANC) visits was categorised as ‘≥4 visits’ (which is recommended as adequate by the WHO), and ‘<4 visits’.
Timing of first ANC visit	Timing of the first ANC visit was categorised as ‘visit in the first trimester (or first 3 months), which is recommended as adequate by the WHO, and ‘after first 3 months’.
Place of delivery	Place of delivery was grouped as ‘medical facility’ or ‘home’.
Distal or socioeconomic factors
Social factors
Religion	Women were categorised into the following religious groups: ‘Hindu’, ‘Muslim’, ‘Christian’ and ‘Others’ which included several groups with small numbers such as Sikh, Buddhists, etc.
Place of residence	Place of residence was grouped into urban and rural.
Social group	Women were categorised into the following social groups: ‘Schedule caste (SC)’, ‘Schedule tribe (ST)’ and ‘Others’ SC and ST are officially designated groups of historically disadvantaged populations in India ‘Others’ included the general social class and other backward classes
Economic factors
Education	Maternal education at the time of the survey was categorised into: illiterate, primary school or below, secondary school, tertiary and above.
Occupation	Based on occupational status, women were grouped as ‘being in paid employment’ or ‘not in paid employment’.
Economic status	Asset index was used to measure the economic status of the participants. Asset index scores were calculated and the study sample was divided into quintiles ranging from the lowest (quintile 1) to highest (quintile 5) socioeconomic status.
Pregnancy complication
Anaemia during pregnancy	This is a derived variable based on questions related to the following signs and symptoms: paleness, giddiness, weakness, excessive fatigue.