The Study of Maternal Factors and Their Association with Risk of Preterm Birth

Objective

The objective is to study maternal factors and their association with preterm birth (PTB). We hypothesize that certain maternal factors increase the risk of PTBs.

Design

A retrospective study recruiting women in labor at WWRC from June 2022 until February 2023.

Method

A cohort of 163 cases of which 59 (36.2%) were PTB (gestational age: <37 weeks) and 101 (62%) term births (gestational age: ≥ 37 weeks) were recruited.

Clinical and demographic data of patients such as age, BMI, glycemic status, blood pressure (BP) status, and Group B streptococcal (GBS) infection status were collected via Cerner, the hospital’s electronic medical records.

Results

For maternal age, 9 PTBs (15.3%) and 5 TBs (5%) were born to mothers aged ≤25years, 39 PTBs (66.1%) and 71 TBs (70.3%) were born to mothers aged >25- ≤35 years, and 11 (18.6%) PTBs and 25 TBs (24.8%) were born to mothers aged >35 years.

In terms of BMI, 2 PTBs (3.4%) and 4 TBs (3.9%) were born to underweight mothers (BMI: <18.5), 18 PTBs (30.5%) and 39 TBs (38.6%) were born to normal weight mothers (BMI: 18.5-24.9), and 39 PTBs (66.1%) and 58 TBs (57.4%) were born to overweight mothers (BMI: >25).

For glycemic status, 40 PTBs (67.8%) and 71 TBs (70.3%) were born to non-diabetic mothers, 8 PTBs (13.6%) and 24 TBs (23.7%) were born to mothers with gestational diabetes mellitus (GDM), 8 PTBs (13.6%) and 2 TBs (2%) were born to mothers with type 1/type 2 diabetes mellitus (DMI/DMII), and 3 PTBs (5.1%) and 4 TBs (4%) were of unknown diabetes status.

As for blood pressure (BP) status, 55 PTBs (93.2%) and 98 TBs (97%) were born to mothers with normal BP range (<120/80), and 4 PTBs (6.8%) and 3 TBs (3%) were born to mothers with abnormal BP status (preeclampsia, gestational hypertension, or chronic hypertension).

For GBS status, 18 PTBs (30.5%) and 20 TBs (19.6%) were born to GBS-positive mothers, 33 PTBs (55.9%) and 78 TBs (77.2%) were born to GBS-negative mothers, and 8 PTBs (13.6%) and 3 TBs (3%) were of unknown GBS status.

Conclusion

Our current data suggests that maternal age, BMI, and GBS status are the most likely maternal factors associated with PTB. However, a larger sample size is necessary to support such findings. Future studies aim to recruit further cases including additional maternal factors such as preterm history, ethnicity, and presence of chorioamnionitis.