Keywords
fetal doppler - fetal ultrasound - preterm birth - Samrakshan India
Background
There are an estimated 15 million preterm births (PTB) each year with a global prevalence
of 10.6%.[1] India contributes nearly 25% to the annual global prevalence of PTB although population-based
estimates of PTB for India are not available.[1] Advances in health care and neonatal intensive care services have translated to
the survival of millions of preterm children to adulthood but with a higher risk of
adverse health events.[2]
[3]
[4]
[5]
[6] Preterm survivors have a 30 to 50% higher all-cause mortality as young adults compared
with term survivors and strong associations with metabolic syndrome, hypertension,
diabetes, and noncommunicable chronic diseases.[2]
[3]
[4]
[5]
[6]
[7] In this manuscript, we present the changes in the preterm birth rate compared with
the baseline year after initiating a third-trimester screening protocol in the Samrakshan
program.
Methodology
The Samrakshan program of IRIA focused on clinical stage-based management of fetal
growth restriction (FGR) in the third trimester integrating fetal Doppler studies
with routine trimester-specific antenatal scans.[8]
[9] Mean uterine artery pulsatility index (PI), umbilical artery PI, middle cerebral
artery (MCA) PI, and cerebroplacental ratio (CPR) were assessed for all third-trimester
pregnant women in the program and a mean uterine artery PI > 95th centile and/or umbilical
artery PI > 95th centile, MCA PI < 5th centile, and CPR < 5th centile was considered
an abnormal Doppler study.[8] The Barcelona protocol was used to categorize FGR with stage 1 FGR defined as an
estimated fetal weight (EFW) < 3rd percentile with or without an abnormal Doppler
study or an EFW < 10th percentile with an abnormal Doppler study.[8] Follow-up Doppler studies were performed based on the clinical staging of FGR as
recommended by the Barcelona protocol.[8]
[9] The results of the Doppler studies were discussed with the managing obstetrician
to plan childbirth. Radiologists participating in Samrakshan followed up with the
managing obstetrician to collect data on childbirth outcomes from September 2019 to
February 2022. A preterm birth was defined as childbirth > 24 and < 37 gestation weeks.
The data were grouped year wise and the period from September 2019 to August 2020
(the first year of Samrakshan) was considered as the baseline to compare the trend
of PTB rates in the program.
Results
Data on childbirth outcomes were available from five states, namely, Kerala, Maharashtra,
Madhya Pradesh, Tamil Nadu, and Uttar Pradesh, for 522 women in 2019–2020, 589 women
from September 2020 to August 2021 and 214 women from September 2021 to February 2022.
From 2019–2022, 249 (18.33%, 95% CI: 16.34, 20.54) women had PTB with 221 (16.67%,
95% CI: 14.73, 18.75) PTBs between 34 and 37 gestation weeks and 22 (1.66%, 95% CI:
1.10, 2.50) PTBs at gestation < 34 weeks. The overall preterm birth rates showed a
significant (chi-square p < 0.001) declining trend each year from 23.18% (n = 121) in 2019–2020 to 16.81% (n = 99) in 2020–2021 and 10.75% (n = 23) in 2021–2022. Preterm births < 34 gestation weeks showed a declining trend
from 1.92% in 2019–2020 to 1.70% in 2020–2021 and 0.93% in 2021–2022. An abnormal
Doppler study (OR: 2.62, 95% CI: 1.95, 3.53), FGR (OR: 2.47, 95% CI: 1.74, 3.49) and
maternal pre-eclampsia (PE) (OR: 3.49, 95% CI: 2.02, 6.02) were significantly associated
with PTB.
We observed a significant reduction (p < 0.001) in proportion of women with stage 1 FGR and PE in this population compared
with the baseline ([Table 1]). Additionally, we observed a significant reduction of PTB (p < 0.001) in the normal population of pregnant women without FGR or PE ([Table 1]). The reduction in PTB in women with small for gestational age (SGA) babies was
not statistically significant (Fisher exact p = 0.80). The declining trend in PTB resulted in a significant gain in mean birthweight
(one-way analysis of variance [ANOVA] F = 3.80, p = 0.02) from 2715.86 (518.74) g in 2019–2020 to 2803.56 (470.33) g in 2021–2022.
Table 1
Proportion of preterm birth by subgroups of pregnant women
|
Preterm births in subgroups of pregnant women
|
2019–2020
(September to August)
n = 522
|
2020–2021
(September to August)
n = 589
|
2021–2022
(September to February)
n = 214
|
|
No fetal growth restriction (FGR)
|
19.63%
|
15.71%
|
9.76%
|
|
Stage 1 FGR
|
34.15%
|
24.14%
|
4.17%
|
|
Small for gestational age
|
17.78%
|
12.50%
|
13.04%
|
|
Normal Doppler study
|
19.09%
|
12.71%
|
9.83%
|
|
No pe-eclampsia
|
21.13%
|
16.25%
|
10.90%
|
|
Pre-eclampsia
|
64.00%
|
27.59%
|
0.00%
|
Conclusion
The declining trend of PTB rates in the Samrakshan program shows that reduction of
PTB is an added benefit of the integration of fetal Doppler studies in the third trimester
of pregnancy. The reduction of PTB can be attributed to the surveillance and planning
of childbirth based on clinical stage-based classification of FGR and was also observed
in normal pregnancies without FGR and PE in Samrakshan. The significant reduction
in PTB rates for stage 1 FGR and women with PE is important, considering the high
incidence of PE and FGR in India[8] and can lead to a significant reduction in the absolute numbers of PTB in India.
The integration of fetal Doppler studies may impact fetal causes of PTB more than
maternal causes for PTB. However, we are unable to comment further on this as we had
not collected data on the differential causes of PTB in Samrakshan. If we extrapolate
the results from Samrakshan to India, PTB would have reduced from 6.2 million in 2019–2020
to 2.9 million in 2021–2022 in India. However, these absolute numbers must be interpreted
with caution as our data may not be representative of the entire population of pregnant
women in India.
