Table 3:

Management Considerations for Preexisting Diabetes in Pregnancy

Diagnostic steps
	Preconception	First Trimester	Second/Third Trimesters	Postpartum
Laboratory studies	- HbA1c - Urine ACR or PCR - TSH in T1DM
Clinical screenings	- Discuss contraception (ideally LARC) - OSA screening in obesity - Retinal exam -consider CAD screening if multiple risk factors	- Close SMBG (7x/day) +/− CGM - Retinal exam if not done preconception, and repeat evaluations as indicated		- Discuss contraception (LARC)
Fetal assessment			-Detailed anatomical survey by US at 18-20 weeks -Consider fetal echocardiography -Evaluate fetal growth (third trimester) -Formal fetal monitoring (often started at 32 weeks; nonstress test, biophysical profile)
Therapeutic steps
	Preconception	First Trimester	Second/Third Trimesters	Postpartum
Non-Pharmacologic Interventions	- Weight optimization via lifestyle modifications - Referral and follow-up with nutritionist to review diet +/− ICR			- Lactation consultation - Consider ongoing nutrition support
Pharmacologic interventions	- Optimize glucose with HbA1c goal <6.5% - May require initiation of insulin in T2DM - Stop non-insulin agents including SU, TZD, DPP4i, GLP-1RA, SGLT2i a - Initiation of daily prenatal vitamin (≥400mcg folic acid, 1000mg elemental calcium, 600IU vitamin D per day) - Switch off ACEi/ARB to accepted anti-hypertensive agentsb - Stop statin	- Initiate/titrate insulin (typically period of increased insulin sensitivity)	- ASA 60-150mg (usual dose 81mg) started between 12-28 (ideally before 16) weeks to minimize risk of PET -Titrate insulin (typically period of increased insulin resistance) -IV insulin typically administered during labor	- Decrease insulin immediately post-partum due to high insulin sensitivity: Up to 50% pre-pregnancy needs in T1DM, and consider stopping insulin in T2DM - Metformin safe for breastfeeding

Abbreviations: HbA1c=hemoglobin A1c; ACR=urine albumin-to-creatinine ratio; PCR=urine protein-to-creatinine ratio; CAD=coronary artery disease; CGM=continuous glucose monitoring, TSH=thyroid stimulating hormone; LARC=long-acting reversible contraception; T1DM=type 1 diabetes; OSA=obstructive sleep apnea; SMBG=self-monitoring of blood glucose; US=ultrasound; ICR=insulin-to-carbohydrate ratios; T2DM=type 2 diabetes; SU=sulfonylureas; TZD=thiazolidinediones; DPP4i=dipeptidyl peptidase 4 inhibitor; GLP-1RA=GLP-1 receptor agonist; SGLT2i=sodium glucose cotransporter 2 inhibitor; IU=international units; ACEi=angiotensin converting enzyme inhibitor; ARB=angiotensin receptor blocker; ASA=aspirin; PET=preeclampsia

^aMetformin has been continued safely in some pregnancies, including in polycystic ovarian syndrome, although there is insufficient data to recommend use during pregnancy

^bAccepted anti-hypertensive agents for use in pregnancy: labetalol, hydralazine, methyldopa, nifedipine