Lab Work You Need When Trying To Conceive

Dr. Jolene BrightenPublished: Last Reviewed: Fertility, Lab Testing, Preconception & Fertility Leave a Comment

With rising rates of fertility challenges, more women are taking time and energy to prepare their bodies for pregnancy. Optimizing your health beforehand improves your chances of conception, a healthy pregnancy, and a healthy baby. An important part of pregnancy preparation is lab work for trying to conceive. 

Taking a thorough look at nutrition and health markers helps identify areas to focus on preconception. Preparing for pregnancy includes diet changes to optimize nutrition and hormone levels, addressing underlying health concerns, and adjusting your lifestyle to optimize health and prepare for parenthood. 

This article takes a deep dive into prenatal lab work with recommended tests, optimal ranges, and tips for promoting health in specific areas, including utilizing my the best pregnancy supplements for optimizing preconception health. 

Preparing for Pregnancy

In addition to prenatal lab work, which I’ll focus on shortly, the preconception period is the ideal time to begin taking a prenatal vitamin. Ideally, you’ll want to start taking a quality prenatal vitamin at least three to six months before trying to conceive. In addition, I recommend supplementing with omega-3 fats before, during, and after pregnancy.

If you are a woman in your reproductive years and could become pregnant or desire a future pregnancy, you can begin taking prenatal nutrients now. Read more about the best prenatal vitamins here

Nutrition is foundational for a healthy pregnancy. Focus on colorful, fiber-rich plant foods, healthy fats, and protein. Check out my article What to Eat to Get Pregnant

In addition, make sure you are getting enough sleep, managing stress, and reducing toxin exposures. Building these habits now will be so supportive when your baby arrives. 

And note that preconception health isn’t just important for women, male partners benefit just as much. New data suggests that sperm health is crucial for not only conception, but a healthy pregnancy and healthy child too. Learn more about male fertility here

What Prenatal Lab Work Do You Need

What Prenatal Lab Work Do You Need?

Below you will find information about the lab work I recommend the most when you are considering pregnancy. Other helpful tests may be recommended depending on your circumstance, medical history, family history, and other factors. Work closely with your naturopathic doctor for testing and any necessary treatment protocols. 


It’s no surprise that hormone balance is crucial for maintaining a healthy pregnancy, and optimizing hormone status before pregnancy is ideal. In addition to testing sex hormones in cases of irregular periods, PCOS, and other signs of hormone imbalance, testing thyroid hormones like T3, T4, TSH, and others, is important. 

Full Thyroid Panel 

A full thyroid panel assesses thyroid health, which is crucial during pregnancy. Thyroid hormones drive the metabolic rate that increases with pregnancy. Thyroid autoimmunity may be a factor in miscarriage. In addition, thyroid hormone is involved in follicle maturation, making it crucial for healthy ovulation. Keep in mind that biotin, which is included in most quality prenatals, can affect this test and should be discontinued 2 days prior to testing. It doesn’t affect your thyroid directly, but can interfere with the test results. 

Complete thyroid labs include: 

Thyroid MarkerOptimal RangeStandard Lab Range
TSH0.5-2.5 uIU/mL(0.45 – 4.5 uIU/mL)
Free T41-1.77(0.82 – 1.77 ng/dL)
Free T33-4(2.0-4.4 pg/mL)
Reverse T3<15(9.2-24.1 ng/dL)
Thyroid peroxidase (TPO) antibodies(0-34 IU/mL) (0-34 IU/mL) 
Anti-thyroglobulin(0.0-0.9 IU/mL)(0.0-0.9 IU/mL)

To optimize your thyroid hormones:

  • Take a prenatal that includes vital thyroid nutrients, including selenium, zinc, and vitamin A. Our Prenatal Plus was designed with the thyroid in mind, which is why it contains the ideal balance of selenium and iodine.
  • Eat a nutrient-dense, anti-inflammatory diet.
  • Heal the gut, as discussed in this article.
  • Address autoimmunity or individual concerns. For more on pregnancy with hypothyroidism, read this article
  • Use a high quality Omega-3 fatty acid. This is an excellent way to support pregnancy and help your thyroid function at its best.
Full Thyroid Panel

General Health 

A CBC, CMP, and Hs-CRP are part of the general health lab work you may get annually. Your CMP will usually be done fasted, while the others can be done non-fasted, either way,  be sure to drink plenty of water to stay hydrated. 

Complete Blood Count (CBC)

A complete blood count (CBC) helps evaluate overall health and detect infections or blood disorders. It measures the health of your blood cells and includes a red blood cell count, white blood cells, and measurements of the cells. 

Complete blood count normal reference ranges are: 

  • WBC (3.4-10.8 x 10E3/uL)
  • RBC (3.77-5.28 x10E6/uL)
  • Hemoglobin (11.1-15.9 g/dL)
  • Hematocrit (34.0-46.6%)
  • MCV (79-97 fL)
  • MCH (26.6-33.0 pg)
  • MCHC (31.5-35.7 g/dL)
  • RDW (11.7-15.4%)
  • Platelets (150-450 x10E3/uL)
  • Neutrophils (1.4-7.0x10E3/uL)
  • Lymphs (0.7-3.1x10E3/uL)
  • Monocytes (0.1-0.9x10E3/uL)
  • Eos (0.0-0.4x10E3/uL)
  • Baso (0.0-0.2x10E3/uL)
  • Immature Grans (0.0-0.1x10E3/uL)

To optimize your CBC:

  • Take a prenatal vitamin. 
  • Optimize iron status (see more on ferritin below).
  • Eat foods rich in folate, including avocado, asparagus, lentils, and dark leafy greens.
  • Eat foods rich in vitamin B12, including eggs, grass-fed beef, and wild fish.

Complete Metabolic Panel (CMP)

A complete metabolic panel (CMP) looks at essential markers for metabolism, liver, and kidney function, along with electrolytes, protein, and other markers. Sometimes medication use will affect these labs, and monitoring CMP is a way to monitor your body’s response to medications. 

Your naturopathic physician or functional medicine doctor may want to see some of these labs in tighter ranges. For example, fasting blood glucose has a standard range of 70-99 mg/dL, but once you get over 100, you’ll be in the pre-diabetes category. A more optimal range is 75-85 mg/dL, and values rising over time may be an early sign of insulin resistance. 

Normal complete metabolic panel levels are: 

  • Glucose (70-99mg/dL)
  • BUN (8-27mg/dL)
  • Creatinine (0.76-1.27mg/dL)
  • eGFR (>59 mL/min/1.73)
  • BUN/Creatinine Ratio (10-24)
  • Sodium (134-144 mmol/L)
  • Potassium (3.5-5.2 mmol/L)
  • Chloride (96-106 mmol/L)
  • Carbon Dioxide, Total (20-29 mmol/L)
  • Calcium (8.6-10.2 mg/dL)
  • Protein, Total (6.0-8.5 g/dL)
  • Albumin (3.8-4.8 g/dL)
  • Globulin, Total (1.5-4.5 g/dL)
  • A/G Ratio (1.2-2.2)
  • Bilirubin, Total (0.0-1.2 mg/dL)
  • Alkaline Phosphatase (44-121 IU/L)
  • AST (0-40 IU/L)
  • ALT (0-44 IU/L)

To optimize your CMP:

C-Reactive Protein (CRP)

C-reactive protein is a marker of inflammation and cardiac risk. The lab test is available as CRP or hs-CRP, a high-sensitivity test. The “hs” stands for highly sensitive. This is what a naturopathic or functional medicine provider will order to catch low-grade inflammation.

The standard lab range for Hs-CRP is 0.00-3.00 mg/dL. With levels below 1.0 mg/dL having the lowest cardiac risk, average risk is 1.00-3.00 mg/dL, and high risk is above 3.00 mg/dL. 

To optimize CRP levels: 

  • Eat an anti-inflammatory diet that includes lots of plant foods and healthy fats like olive oil, and nuts.
  • Include low-mercury fish like wild salmon and sardines 3-5 times each week. 
  • Take a fish oil supplement containing EPA and DHA, such as Omega Plus.
  • Optimize sleep. As I talk about in Is This Normal, poor quality sleep can lead to inflammation, adrenal dysfunction, and a myriad of hormone issues, like an inability to ovulate.
best prenatal vitamins

Vitamins & Minerals

Pregnancy and breastfeeding are highly nutrient depleting events for the body—that is, unless you build your nutrient stores before pregnancy and continue them throughout pregnancy and postpartum. Nutrients you get from food and your prenatal vitamins support  your baby’s health in the womb and beyond. In fact, because breast milk is void of substantial iron, your stores of this nutrient help your baby for the first 6 months of their life. Optimizing nutrition status before and during pregnancy supports a healthy pregnancy and lactation too. 

Vitamin D

Vitamin D is a common nutrient deficiency and a nutrient essential for fertility, pregnancy, and lactation. Vitamin D has many benefits for immunity, bone health, and how your genes function. Low vitamin D levels during pregnancy increase the risk for preterm birth, postpartum depression, pre-eclampsia, and gestational diabetes in the mom, and childhood asthma, eczema, and other immune conditions in the child. 

Testing vitamin D levels is essential to dose supplementation, as most people won’t be able to maintain optimal levels through food alone. We also synthesize vitamin D from the sun, which is our primary source. It’s not enough to live in a sunny location, you have to actually spend time outside, without sunscreen. That’s why even in this sunniest of locations, people still have a vitamin D deficiency. 

Normal vitamin D levels (measured as 25-hydroxy vitamin D) are 30.00-100 ng/mL. Research supports the benefits of maintaining levels of 50 ng/mL to 80 ng/mL  before and during pregnancy.  Taking a minimum of 1,000 IU of vitamin D can help support someone who is already sufficient in vitamin D. But if your numbers are low, you may need to supplement higher.

To optimize your vitamin D levels:

  • Take a quality prenatal with vitamin D. Prenatal Plus contains 30mcg/1200 IU vitamin D3.
  • Supplement with additional vitamin D to maintain optimal blood levels. Vitamin D3/K3 contains 50mcg/2000IU per serving, and the liquid formula allows for easy dose adjustment.
  • Vitamin D works with magnesium, vitamin A, vitamin K2, and other nutrients, so overall nutrition is essential. 
  • Get healthy sun exposure. 

Magnesium & Zinc, RBC

Magnesium and zinc are critical minerals for metabolism, fertility, pregnancy, immunity, and more. Male and female fertility, placental health, and limb growth during pregnancy requires zinc. Magnesium is involved in fetal programming, a critical point in which organs develop, during pregnancy and can help prevent adult diseases. Read about more benefits of magnesium here

The preferred way to measure magnesium and zinc is inside red blood cells. The reference ranges are: 

  • Zinc, RBC (878-1660 ug/dL)
  • Magnesium, RBC (4.2-6.8 mg/dL)

To optimize magnesium and zinc:


Iron is another crucial mineral for a healthy pregnancy, allowing blood volume to expand. Ferritin is the storage form of iron and the most sensitive test for iron deficiency anemia. Recent research suggests maternal iron status during pregnancy influences neurodevelopment. You don’t want low ferritin (anemia) or high levels (iron overload). Often, your ferritin levels will alert you to a problem before your CBC shows changes.

Ferritin levels should be between 15 and 150 ng/mL. Levels above 50 are more optimal in the preconception period, with the ideal being closer to 80. 

To optimize ferritin levels:

  • Test ferritin before pregnancy, throughout pregnancy, and after pregnancy to adjust diet and supplementation. 
  • To increase ferritin, eat iron-rich foods like grass-fed beef and shellfish. 
  • Take a prenatal vitamin with a highly absorbable form of iron, such as Prenatal Plus. Ferrous sulfate, which is the most commonly prescribed, is poorly absorbed and can result in constipation and stomach upset.


Homocysteine is an amino acid marker linked to heart disease, but has utility in pregnancy. High homocysteine is linked to MTHFR gene mutations and infertility, indicating poor methylation and the need for more folate and vitamin B12. Methylation is critical for pregnancy as it is required for cell division and preventing neural tube defects. Elevated homocysteine can indicate problems with folate, vitamin B12, or vitamin B6

The reference range for homocysteine levels is 0.0-14.5 umol/L, although optimal levels fall between 3.9-7.3 mmol/L.

To maintain normal homocysteine levels:

  • Take a quality prenatal that includes folate, vitamin B12, vitamin B6, and the full B vitamin complex, such as Prenatal Plus.
  • Eat methylation-supportive foods, including leafy greens, beans, avocados, quality animal protein, beets, eggs, turmeric, and more.
  • Avoid synthetic folic acid and choose methylfolate instead. Read more about the MTHFR gene mutation here

Blood Sugar

Healthy blood sugar control leads to a healthy pregnancy and prevents gestational diabetes and other metabolic disease. 

Hemoglobin A1C

Hemoglobin A1C is a 3-month average of blood sugar values. An ideal hemoglobin A1C before pregnancy correlates with a normal glucose tolerance test during pregnancy, the test for gestational diabetes. 

The hemoglobin A1C normal range is 4.8-5.6%. Levels between 5.7 and 6.4% indicate prediabetes, and above 6.4% is diagnostic of diabetes. 

To optimize your hemoglobin A1C:

  • Eat balanced whole-food meals, including protein, healthy fat, and fiber-rich carbs.
  • Minimize or avoid refined carbohydrates like sugar, flour, and ultra-processed foods.
  • Address PCOS, which may be the underlying contributor to high blood sugar in some cases. Read Getting Pregnant with PCOS for more information. 

Fasting Insulin 

Fasting insulin is another way to assess metabolic health and issues with blood sugar control, such as insulin resistance. Insulin is the hormone that helps move glucose (blood sugar) from the bloodstream into the cells, but high insulin may indicate that the cells have a hard time getting the signal, which can be a problem in pregnancy. 

Normal fasting insulin levels are 2.6-24.9 uIU/mL; however, more optimal levels are at the low end of the range. Insulin levels that are too low can have a negative impact on thyroid levels so ensuring adequate carbohydrate is really important for fertility.

To optimize fasting insulin, use all the tools and strategies to balance blood sugar, including exercise, sleep, stress management, diet, and supplements. 

Complete Stool Analysis 

A complete stool analysis is a stool test that assesses microbiome health, gut infections, digestive function, inflammation, and more. It’s not a blood test but an at-home stool collection often ordered by naturopathic or functional medicine doctors. 

Since gut health is essential for overall health, the vaginal microbiome, metabolism, hormone balance, fertility, and so much more, this test is highly recommended during the preconception period. You can use the results to optimize your microbiome, which you pass on to your baby through the placenta, during delivery, and with breastfeeding. 

Examples of complete stool tests are, CSA by Doctor’s Data, and  GI MAP by Diagnostic Solutions Lab, and GI Effects by Genova. Please work with your naturopathic or functional medicine provider for testing, result interpretation, and treatment. 

To optimize gut health prior to pregnancy:


You won’t regret taking time before trying to conceive to care for your own health and prepare your body for pregnancy. Use the lab tests listed here to get a complete picture of your health and fertility, so you can make changes to promote conception and healthy pregnancy. 

In addition to building healthy nutrition and lifestyle habits, my Pregnancy Support Kit contains three supplements to support your journey to pregnancy and beyond. It includes Prenatal Plus, a quality prenatal vitamin and mineral supplement containing active nutrient forms, Omega Plus for concentrated omega-3 fats, and Women’s Probiotic for targeted microbiome support.

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  1. Dong AC, Morgan J, Kane M, Stagnaro-Green A, Stephenson MD.. Subclinical hypothyroidism and thyroid autoimmunity in recurrent pregnancy loss: a systematic review and meta-analysis.. Fertil Steril. 2020. 113. 587-600.e1.
  2. Marshall NE, Abrams B, Barbour LA, et al.. The importance of nutrition in pregnancy and lactation: lifelong consequences. Am J Obstet Gynecol.. 2022. 226. 607-632.
  3. Pilz S, Zittermann A, Obeid R, et al.. The Role of Vitamin D in Fertility and during Pregnancy and Lactation: A Review of Clinical Data.. Int J Environ Res Public Health. 2018. 15. 2241.
  4. Mansur JL, Oliveri B, Giacoia E, Fusaro D, Costanzo PR.. Vitamin D: Before, during and after Pregnancy: Effect on Neonates and Children. Nutrients. 2022. 14. 1900.
  5. Garner TB, Hester JM, Carothers A, Diaz FJ.. Role of zinc in female reproduction.. Biol Reprod.. 2021. 104. 976-994..
  6. Fanni D, Gerosa C, Nurchi VM, et al.. The Role of Magnesium in Pregnancy and in Fetal Programming of Adult Diseases.. Biol Trace Elem Res. 2021. 199. 3647-3657.
  7. Quezada-Pinedo HG, Cassel F, Duijts L, et al.. Maternal Iron Status in Pregnancy and Child Health Outcomes after Birth: A Systematic Review and Meta-Analysis. Nutrients.. 2021. 13. 2221.
  8. Ménézo Y, Patrizio P, Alvarez S, et al.. MTHFR (methylenetetrahydrofolate reductase: EC SNPs (single-nucleotide polymorphisms) and homocysteine in patients referred for investigation of fertility.. J Assist Reprod Genet.. 2021. 38. 2383-2389.
  9. Shapiro AJ, Holden EC, McGovern PG, Alderson D, Morelli SS.. Comparison of 2-Hour Oral Glucose Tolerance Test and Hemoglobin A1C in the Identification of Pre-Diabetes in Women with Infertility and Recurrent Pregnancy Loss.. Clin Med Insights Reprod Health. 2019. 13. 1179558119831280.
  10. Skoracka K, Ratajczak AE, Rychter AM, Dobrowolska A, Krela-Kaźmierczak I.. Female Fertility and the Nutritional Approach: The Most Essential Aspects. Adv Nutr. 2021. 12. 2372-2386.
About The Author

Dr. Jolene Brighten

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Dr. Jolene Brighten, NMD, is a women’s hormone expert and prominent leader in women’s medicine. As a licensed naturopathic physician who is board certified in naturopathic endocrinology, she takes an integrative approach in her clinical practice. A fierce patient advocate and completely dedicated to uncovering the root cause of hormonal imbalances, Dr. Brighten empowers women worldwide to take control of their health and their hormones. She is the best selling author of Beyond the Pill and Healing Your Body Naturally After Childbirth. Dr. Brighten is an international speaker, clinical educator, medical advisor within the tech community, and considered a leading authority on women’s health. She is a member of the MindBodyGreen Collective and a faculty member for the American Academy of Anti Aging Medicine. Her work has been featured in the New York Post, Forbes, Cosmopolitan, Huffington Post, Bustle, The Guardian, Sports Illustrated, Elle, and ABC News. Read more about me here.