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Relationship between maternal hypothyroidism and gestational diabetes mellitus and its impact on maternal and fetal outcomes
*Corresponding author: Jupally Jhansi, Department of Obstetrics and Gynaecology, Rangaraya Medical College, Kakinada, Andhra Pradesh, India. jhansijupally@gmail.com
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Received: ,
Accepted: ,
How to cite this article: Jhansi J, Padmaja R, Gorle R, Cheedi V. Relationship between maternal hypothyroidism and gestational diabetes mellitus and its impact on maternal and fetal outcomes. RMC Glob J. 2026;2:20–23. doi: 10.25259/RMCGJ_24_2025
Abstract
Objectives: Diabetes mellitus and hypothyroidism are among the most common endocrinopathies during pregnancy. They are associated with both maternal and fetal complications. The objective of the study is to assess the maternal and fetal outcomes in patients with dual endocrinopathy versus gestational diabetes mellitus (GDM) alone.
Material and Methods: A retrospective cohort study was conducted at GGH, Kakinada, in the Department of Obstetrics and Gynaecology from June 2023 to May 2024. A total of 50 cases and 50 controls were analysed for complications such as preeclampsia, need for cesarean section, malpresentation, preterm birth, PROM, abruption of placenta, Doppler changes, respiratory distress, and macrosomia in neonates.
Results: Age above 30 years is a key factor in the development of dual endocrinopathy. Women with dual endocrinopathy had an increased risk of preeclampsia, cesarean section, and higher rate of macrosomia in women with dual endocrinopathy.
Conclusion: Dual endocrinopathy is associated with increased maternal and fetal complications. It is important to screen women who have been diagnosed with one of these for the other. These patients should be considered high-risk pregnancies and are to be followed up to prevent adverse effects.
Keywords
Fetal outcomes
Gestational diabetes mellitus
Hypothyroidism
Maternal outcomes
Pregnancy complications
INTRODUCTION
The prevalence of gestational diabetes mellitus (GDM) is 5%–18%. It is an established fact that GDM increases maternal and fetal morbidity.
Maternal effects
Predisposes to preeclampsia, chorioamnionitis, polyhydramnios, preterm labor, urinary tract infections, need for caesarean section, instrumental delivery, postpartum hemorrhage, surgical wound infection, and sepsis. It has long-term risks of developing type II DM and other cardiovascular or renal disorders.
Fetal effects
Congenital malformations, macrosomia, growth restriction, sudden IUFD, chronic hypoxia, shoulder dystocia, birth asphyxia, chemical imbalances after birth, RDS, cardiovascular disease, and impaired cognitive and motor function. Maternal hypothyroidism is known to complicate 2–12 per 1000 pregnancies. If the maternal thyroid gland is unable to cope with increased demands of pregnancy, it produces symptoms similar to a pathological state. Maternal thyroxine levels are very important for the neuropsychological development of the growing fetus. Till the 12th week of gestation, the mother’s thyroid gland is the only source of thyroxine for the growing fetus. Though the fetus develops its own functional gland after this, maternal thyroxine is still required for normal fetal development. Hypothyroidism in pregnancy has an increased risk of the development of gestational diabetes mellitus.1 Previous studies have suggested a possible worsening of fetal outcome with dual endocrinopathy. There has been a call for further research into the effects of hypothyroidism alone and associated with other endocrinopathies in pregnancy to allow for the development of screening and treatment protocols for the same. Hence, in our study, we have sought to determine the effects of the two most common endocrinopathies in India. We have studied the maternal and fetal effects of hypothyroidism in patients with GDM versus GDM alone. The diagnostic criteria and management approach followed in this study were based on standard obstetric reference guidelines.2,3
Aims
The study aimed to determine the maternal and fetal outcomes in patients with dual endocrinopathy versus GDM alone.
MATERIAL AND METHODS
A retrospective cohort study was conducted in the GGH, Kakinada, Department of Obstetrics and Gynaecology from June 2023 to May 2024. A total of 50 cases and 50 controls were analysed for complications such as preeclampsia, need for cesarean section, malpresentation, preterm birth, PROM, abruption of placenta, Doppler changes, respiratory distress, and macrosomia in neonates.
Inclusion criteria
The inclusion criteria involved:
A patient with both gestational diabetes mellitus and hypothyroidism as cases. Patients with gestational diabetes mellitus were used as controls.
A TSH level of more than 4 µIU/ml was considered the cutoff value.
Screening according to DIPSI protocol after 75 g glucose intake was done to diagnose gestational diabetes mellitus, with a cut-off blood sugar level of 140 mg/dl after 2 hours, and confirmation is done with the Oral Glucose Tolerance Test.
Exclusion criteria
The exclusion criteria involved:
Overt diabetics
Congenital hypothyroidism
Patients having other significant medical comorbidities.
RESULTS
This study showed that age above 30years is a risk factor for the development of dual endocrinopathy, i.e., both GDM and hypothyroidism, with a p value of 0.01. The comparison of maternal and fetal outcomes between women with GDM alone and those with dual endocrinopathy is summarized in Table 1. The participants with dual endocrinopathy had an increased incidence of Preeclampsia, need for LSCS, with p values being 0.007, 0.009, respectively. Babies with birth weight more than 3.5kg are also seen in greater numbers in patients with dual endocrinopathy when compared to the GDM alone group, with a p-value of 0.006.
| Gestational diabetes alone | Gestational DM+ hypothyroidism | |
|---|---|---|
| Age ( more than 30 years) | 6 | 17 |
| Need for insulin therapy | 16 | 24 |
| Birthweight > 3.5 kg | 7 | 18 |
| History of abortions | 6 | 10 |
| PROM | 6 | 5 |
| Preterm births | 8 | 6 |
| Uteroplacental insufficiency | 7 | 7 |
| History of GDM in previous pregnancy | 6 | 10 |
| Gestational diabetes alone | Gestational DM+ hypothyroidism | |
| History of hypothyroidism in previous pregnancy | 2 | 3 |
| Malpresentations | 8 | 7 |
| Need for LSCS | 20 | 39 |
| De-novo HTN in pregnancy | 12 | 26 |
| Operative vaginal delivery | 5 | 4 |
| Respiratory distress in a baby | 14 | 21 |
| Non reassuring FHR | 12 | 20 |
| Abruption | 1 | 0 |
GDM: Gestational diabetes mellitus, PROM: Premature rupture of membranes, LSCS: Lower segment cesarean section, HTN: Hypertension, FHR: Fetal heart rate.
There is no significant difference statistically among the following parameters, such as preterm birth (p = 0.37), history of abortions (p = 0.1), uteroplacental insufficiency, PROM, malpresentations, postnatal respiratory distress, operative vaginal delivery, need for insulin therapy, and abruption in both groups.
Age above 30 years is a key factor in the development of dual endocrinopathy. Women with dual endocrinopathy had an increased risk of preeclampsia, cesarean section, and a higher rate of macrosomia.
DISCUSSION
Definition of GDM according to ACOG is any degree of glucose intolerance that either commences or is first diagnosed in pregnancy. This is inclusive of women whose glucose tolerance returns to normal after pregnancy, and also those who develop type 2 diabetes. According to the 2017 American Thyroid Association guidelines, the use of pregnancy-specific, population-based reference ranges is recommended. However, if none of the published studies are generalizable to the population of interest, the 2017 guidelines advocate the use of a fixed upper limit of the non-pregnancy upper limit minus 0.5 µIU/l, which is similar to the upper limits in large studies involving iodine-sufficient populations, or a baseline value of 4 µIU/l is to be taken.4
A dual endocrinological combination is an independent risk factor for preeclampsia and the need for cesarean section, as shown by T. Dan (2013).5 Feely and Isles (1979) reported that among people with diabetes, there is a prevalence of overt hypothyroidism of 2.7% and a subclinical prevalence of 30%.6 In previous studies, TSH was found to have a significant positive association with blood glucose levels and a negative association with fetal weight,7 whereas in our study, higher fetal weights were found in patients with hypothyroidism. In another study, this combination of endocrinopathy was found to be independently associated with a higher risk of polyhydramnios.8 No such association was found in our study.
CONCLUSION
Dual endocrinopathy is associated with increased maternal and fetal complications. It is important to screen women who have been diagnosed with one of these for the other. These patients should be considered high-risk pregnancies and are to be followed up to prevent adverse effects. The findings from our study suggest that there is a need for caution regarding gestational diabetes in women with hypothyroidism, especially when they are older than 30 years of age. This study focuses on the importance of increased vigilance towards early detection and management of hypothyroidism.
Ethical approval:
Institutional Review Board approval is not required as it is a retrospective study.
Declaration of patient consent:
The authors certify that they have obtained all appropriate patient consent.
Financial support and sponsorship:
Nil.
Conflicts of interest:
There are no conflicts of interest.
Use of artificial intelligence (AI)-assisted technology for manuscript preparation:
The author confirms that there was no use of artificial intelligence (AI)-assisted technology for assisting in the writing or editing of the manuscript and no images were manipulated using AI.
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