Skip to content
How It Works
Explore
Resources Ask a Question
Who It's For
Patients
Decode results, prep for appointments, weigh options.
Caregivers & advocates
Carry the research load for someone you love.
Providers & clinicians
Resources for patients in your practice.
Log In Ask a Question
PubMed This is a summary of 17 peer-reviewed journal articles Updated
Endocrinology · Maturity-Onset Diabetes of the Young

MODY and Pregnancy: Managing the Maternal-Fetal Conflict

At a Glance

Managing MODY during pregnancy requires a tailored approach based on your specific genetic subtype. In GCK-MODY, management depends on whether your baby inherited the mutation, while HNF1A and HNF4A subtypes typically require transitioning from oral medications to insulin.

Pregnancy with MODY is a unique medical situation because your genetics and your baby’s genetics work together to determine how your blood sugar should be managed [1][2]. Unlike typical gestational diabetes, where the goal is usually just to lower the mother’s blood sugar, MODY management requires a more tailored approach to ensure the baby grows at a healthy rate [3][4].

The GCK-MODY “Conflict”

In GCK-MODY (MODY2), the management of pregnancy depends entirely on whether the baby has inherited the mutation from you. This creates a situation called the maternal-fetal conflict [2][1].

  • If the baby DOES NOT inherit the mutation: The baby’s pancreas is “normal” and senses your slightly elevated blood sugar as a problem. The baby will produce extra insulin to compensate, which can cause them to grow too large (macrosomia) [2][1]. In this case, you may need insulin to protect the baby from overgrowth [3].
  • If the baby DOES inherit the mutation: The baby has the same “higher thermostat” as you. They “agree” with your blood sugar levels and grow at a normal rate [1][5].
  • The Risk of Over-treatment: If you take insulin to lower your blood sugar when the baby also has the mutation, you can actually starve the baby of the glucose they expect, leading to fetal growth restriction (the baby being born too small) [4][2].

Because of this, doctors often use serial ultrasounds to measure the baby’s abdominal circumference. If the baby is growing rapidly (above the 75th percentile), it suggests they did not inherit the gene, and the mother may start insulin [3][1]. Some centers now offer non-invasive prenatal testing (NIPT), a simple blood test for the mother that can determine the baby’s genetic status early in pregnancy [6][7].

Managing HNF1A and HNF4A

For patients with the HNF1A or HNF4A subtypes, the approach is different. While these patients often thrive on oral sulfonylurea tablets, these medications are generally changed during pregnancy [8].

  • The Transition to Insulin: Most guidelines recommend transitioning from oral pills to insulin by the second trimester, if not before conception [8].
  • Why the Switch? Sulfonylureas can cross the placenta and stimulate the baby’s pancreas to release too much insulin. This can lead to the baby being born too large [8].

A Special Note on HNF4A and Hypoglycemia: For babies who inherit the HNF4A mutation, there is an exceptionally high risk of severe neonatal hypoglycemia (very low blood sugar) immediately after birth [9]. This happens due to the mutation itself, which causes fetal hyperinsulinism, not just because of the mother’s medication [10]. It is critical that your delivery team and the NICU are aware of your diagnosis to monitor and treat the baby immediately.

The Importance of Genetic Counseling

Because MODY is inherited in an autosomal dominant pattern, there is a 50% chance that each child will inherit the gene [11][12].

A genetic counselor can be an invaluable part of your care team. They help you:

  1. Understand the risks of transmission to your children [11].
  2. Coordinate the correct testing for family members (cascading screening) [13][14].
  3. Discuss the long-term outlook for your child’s health based on your specific mutation [15].
  4. Navigate the emotional and ethical aspects of genetic testing in children [16].
Subtype Pregnancy Focus Common Management
GCK (MODY2) Fetal growth rate Treatment only if baby is growing too fast [3]
HNF1A (MODY3) Strict glucose control Transition from pills to insulin [8]
HNF4A (MODY1) Fetal size and sugar Transition to insulin; NICU monitoring for baby [8][10]
HNF1B (MODY5) Multi-organ health Insulin; monitor mother’s kidney function [17]

Previous: Treating MODY | Return to Home

Common questions in this guide

Will I need to take insulin if I have GCK-MODY and get pregnant?
You may only need insulin if your baby does not inherit your GCK mutation. Doctors use ultrasounds to monitor the baby's growth; if they are growing too rapidly, you may need to start insulin to prevent them from growing too large.
Is it safe to keep taking sulfonylurea pills during pregnancy?
Most guidelines recommend transitioning from oral sulfonylureas to insulin before or during the second trimester. Sulfonylureas can cross the placenta and cause the baby to produce too much insulin, which can lead to dangerous fetal overgrowth.
How do doctors know if my baby inherited my MODY mutation before birth?
Doctors can sometimes use non-invasive prenatal testing (NIPT), a simple blood test for the mother, to determine the baby's genetic status early in pregnancy. They also use serial ultrasounds to track the baby's abdominal circumference, which gives clues about their genetics.
What are the risks to my baby after birth if I have HNF4A-MODY?
Babies who inherit the HNF4A mutation have an exceptionally high risk of severe low blood sugar immediately after birth due to fetal hyperinsulinism. It is critical that your delivery and NICU teams are prepared to monitor and treat the baby right away.
What are the chances I will pass MODY to my child?
Because MODY follows an autosomal dominant inheritance pattern, there is a 50 percent chance that each child will inherit the genetic mutation from you. A genetic counselor can help coordinate testing and discuss the long-term outlook for your child.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.If I have GCK-MODY, how will we use serial ultrasounds of the baby’s abdominal circumference to decide whether I need insulin?
  2. 2.Is non-invasive prenatal testing (NIPT) available to determine if my baby inherited my GCK mutation?
  3. 3.For HNF1A/HNF4A-MODY, what is the best timing for my transition from sulfonylureas to insulin during pregnancy?
  4. 4.Given the HNF4A mutation risk, will the NICU team be prepared to monitor my baby for severe low blood sugar immediately after birth?
  5. 5.Can you refer me to a genetic counselor to discuss the 50% chance of passing this gene to my child and how to screen them in the future?

Questions For You

Tap a prompt to share your answer — we'll use it plus this page's context to start a tailored conversation.

References

References (17)
  1. 1

    Pregnancy and Neonatal Outcomes in Maturity-Onset Diabetes of the Young: A Systematic Review.

    Ługowski F, Babińska J, Makowska K, et al.

    International journal of molecular sciences 2025; (26(13)) doi:10.3390/ijms26136057.

    PMID: 40649834
  2. 2

    Monogenic diabetes caused by GCK gene mutation is misdiagnosed as gestational diabetes - A multicenter study in Portugal.

    Lima Ferreira J, Voss G, Sá Couto A, Príncipe RM

    Diabetes & metabolic syndrome 2021; (15(5)):102259 doi:10.1016/j.dsx.2021.102259.

    PMID: 34438359
  3. 3

    Pregnancy in Women With Monogenic Diabetes due to Pathogenic Variants of the Glucokinase Gene: Lessons and Challenges.

    Timsit J, Ciangura C, Dubois-Laforgue D, et al.

    Frontiers in endocrinology 2021; (12()):802423 doi:10.3389/fendo.2021.802423.

    PMID: 35069449
  4. 4

    Comment on Rudland et al. Identifying Glucokinase Monogenic Diabetes in a Multiethnic Gestational Diabetes Mellitus Cohort: New Pregnancy Screening Criteria and Utility of HbA1c. Diabetes Care 2016;39:50-52.

    Bhargava A, Siddiqui S, Waghdhare S, Jha S

    Diabetes care 2016; (39(1)):e6 doi:10.2337/dc15-1537.

    PMID: 26696667
  5. 5

    Genotype-Phenotype Characteristics of Turkish Children With Glucokinase Mutations Associated Maturity-Onset Diabetes of the Young.

    Bolu S, Eroz R, Dogan M, et al.

    Indian pediatrics 2020; (57(11)):1037-1039.

    PMID: 32533685
  6. 6

    Bringing precision medicine to the management of pregnancy in women with glucokinase-MODY: a study of diagnostic accuracy and feasibility of non-invasive prenatal testing.

    Hughes AE, Houghton JAL, Bunce B, et al.

    Diabetologia 2023; (66(11)):1997-2006 doi:10.1007/s00125-023-05982-9.

    PMID: 37653058
  7. 7

    Clinical and cost-effectiveness of non-invasive cell-free DNA testing to optimise foetal outcomes for women with monogenic diabetes due to inactivating glucokinase gene mutations: a case series.

    Jones AS, Kevat D, Lee IL, et al.

    Internal medicine journal 2025; (55(12)):2059-2064 doi:10.1111/imj.70262.

    PMID: 41263552
  8. 8

    Management of sulfonylurea-treated monogenic diabetes in pregnancy: implications of placental glibenclamide transfer.

    Shepherd M, Brook AJ, Chakera AJ, Hattersley AT

    Diabetic medicine : a journal of the British Diabetic Association 2017; (34(10)):1332-1339 doi:10.1111/dme.13388.

    PMID: 28556992
  9. 9

    Monogenic diabetes: a gateway to precision medicine in diabetes.

    Zhang H, Colclough K, Gloyn AL, Pollin TI

    The Journal of clinical investigation 2021; (131(3)).

    PMID: 33529164
  10. 10

    GCK-MODY in pregnancy: A pregnant woman with diabetes and a small-for-gestational-age fetus.

    Yau TTL, Yu SCY, Cheng JY, et al.

    Clinical case reports 2022; (10(12)):e6629 doi:10.1002/ccr3.6629.

    PMID: 36483860
  11. 11

    Next generation sequencing targeted gene panel in Greek MODY patients increases diagnostic accuracy.

    Tatsi EB, Kanaka-Gantenbein C, Scorilas A, et al.

    Pediatric diabetes 2020; (21(1)):28-39 doi:10.1111/pedi.12931.

    PMID: 31604004
  12. 12

    Comprehensive genetic screening: The prevalence of maturity-onset diabetes of the young gene variants in a population-based childhood diabetes cohort.

    Johnson SR, Ellis JJ, Leo PJ, et al.

    Pediatric diabetes 2019; (20(1)):57-64 doi:10.1111/pedi.12766.

    PMID: 30191644
  13. 13

    Monogenic Diabetes Accounts for 6.3% of Cases Referred to 15 Italian Pediatric Diabetes Centers During 2007 to 2012.

    Delvecchio M, Mozzillo E, Salzano G, et al.

    The Journal of clinical endocrinology and metabolism 2017; (102(6)):1826-1834 doi:10.1210/jc.2016-2490.

    PMID: 28323911
  14. 14

    Frequency and characterization of mutations in genes in a large cohort of patients referred to MODY registry.

    Breidbart E, Deng L, Lanzano P, et al.

    Journal of pediatric endocrinology & metabolism : JPEM 2021; (34(5)):633-638 doi:10.1515/jpem-2020-0501.

    PMID: 33852230
  15. 15

    Maturity-onset diabetes of the young: From a molecular basis perspective toward the clinical phenotype and proper management.

    Oliveira SC, Neves JS, Pérez A, Carvalho D

    Endocrinologia, diabetes y nutricion 2020; (67(2)):137-147 doi:10.1016/j.endinu.2019.07.012.

    PMID: 31718996
  16. 16

    Diagnosis, treatment and disclosure: A qualitative exploration of participant challenges in a Monogenic Diabetes Registry.

    Noohi F, Sundaresan MS, Naylor RN, Ross LF

    Genetics in medicine : official journal of the American College of Medical Genetics 2023; (25(4)):100019 doi:10.1016/j.gim.2023.100019.

    PMID: 36681871
  17. 17

    Case Report: A case of HNF1B mutation patient with first presentation of diabetic ketosis.

    Ge S, Yang M, Gong W, et al.

    Frontiers in endocrinology 2022; (13()):917819 doi:10.3389/fendo.2022.917819.

    PMID: 35992134

This page provides educational information about managing MODY during pregnancy. It does not replace professional medical advice. Always consult your maternal-fetal medicine specialist, endocrinologist, and OB/GYN about your specific pregnancy care plan.

Get notified when new evidence is published on MODY.

We monitor PubMed for new peer-reviewed studies on this topic and email a short summary when something meaningful changes.