Table 2 Description of maternal and fetal features with target variable chosen in the study.

Maternal anthropometric parameters

1

Age at conception

Continuous variable expressed in number of years

Research shows that a mother’s age can significantly impact fetal development due to pregnancy related issues. This is primarily because age related changes in DNA expression can occur during critical phases of embryonic and fetal development. Mitochondria, the energy-producing organelles, are inherited solely from the mother. Unlike nuclear DNA, mitochondrial DNA lacks robust repair mechanisms, making it more susceptible to mutations as mothers age^28,29

2

Height

Continuous variable expressed in cm

Numerical data expressed in centimetres. Numerous studies suggest a strong relationship between maternal height and birthweight^30,31,32

3

Maternal weight in the first trimester

Continuous variable expressed in kg

Numerical data expressed in kilograms. Studies suggest direct associations between maternal weight, BMI, gestational weight gain, with birthweight and infant adiposity^33,34

4

Body mass index (BMI)

Continuous variable expressed in kg/m²

Maternal BMI is a strong indicator of pregnancy outcomes and serves as a marker for a healthy weight³⁴

5

Parity

Variables are categorised as primigravida, multigravida and encoded

Maternal parity may influence birthweight, with studies showing that newborns of primigravida mothers typically have LBW than those of multigravida mothers^35,36

6

Type of conception

Variables are categorised as natural conception, invitro fertilisation pregnancy, ovulation induction conception, and encoded

The type of conception influences birthweight. Studies also suggest differences in developmental outcomes with assisted reproductive technology^37,38

First-trimester markers-maternal parameters

7

Haemoglobin (Hb)

Continuous variable expressed in g/dl

Early pregnancy hemoglobin levels were measured during the first trimester, and a meta-analysis indicates a strong correlation between these levels and pregnancy outcomes³⁹

8

Glycated hemoglobin (HbA1c)

Continuous variable expressed in %

HbA1c acts as a representative of glycemic control. Poor glycemic control may lead to ketoacidosis, infection, macrosomia, dystocia, spontaneous miscarriage, and congenital anomalies^40,41

9

Thyroid-stimulating hormone (TSH)

Continuous variable expressed in μIU/mL

Numerous studies have explored the effect of TSH on pregnancy, though the findings to date have shown variability and continue to be the subject of ongoing discussion^42,43

First trimester anomaly scan-fetal parameters

10

Nuchal translucency(NT)

Continuous variable expressed in mm

It is the normal accumulation of fluid present behind the neck of the fetus, usually measured between 11–13 weeks 6 days of pregnancy during FTAS⁴⁴

11

Crown-rump length (CRL)

Continuous variable expressed in mm

It is the length from fetal head to the rump for estimating the fetal age during FTAS⁴⁴

12

Pregnancy-Associated Plasma Protein A (PAPP-A)

Continuous variable expressed in MoM

It is a growth factor in normal fetal development and predicts the development of preeclampsia^45,46. Fetal β-hCG and PAPP-A assessment is done in the first trimester to screen for chromosomal abnormalities such as trisomies 21 (Down’s syndrome), 18 (Edwards’ syndrome)and 13 (Patau’s syndrome)⁴⁴

Mid trimester anomaly scan—fetal parameters

13

Bi-parietal-diameter (BPD)

Continuous variable expressed in mm

Transverse view of the fetal head at the level of the thalami⁴⁷

14

Head circumference (HC)

Continuous variable expressed in mm

15

Abdominal circumference (AC)

Continuous variable expressed in mm

Transverse section of the fetal abdomen⁴⁷

16

Femur length (FL)

Continuous variable expressed in mm

The longest axis of the ossified diaphysis of the femur bone is measured⁴⁷

17

Estimated fetal weight (EFW)

Continuous variable expressed in grams

EFW helps in monitoring the fetal growth and development. It is calculated by the composite measurement of BPD, HC, AC, and FL⁴⁷

Risk factors

18

Gestational diabetes mellitus (GDM)

Variables are categorised and encoded as normoglycemic and hyperglycemic

Diabetes mellitus is significantly linked to increased birthweight and a higher likelihood of delivering infants classified as large for gestational age (LGA) or with macrosomia^48,49

19

Hypertension (HTN)

Variables are categorised and encoded as normotensive and hypertensive

Maternal HTN has been established as a significant risk factor associated with LBW⁵⁰

Target variable

20

Birthweight

Expressed in grams

Classified as follows⁵¹

NBW : More than 2500 g

LBW : Less than 2500 g

VLBW : Less than 1500 g