White-tailed Deer Gestation Period: How Long Is a Deer Pregnant?

How long is a white-tailed deer pregnant?

A white-tailed deer carries her fawn for an average of 200 days, or about 6 months and 2 weeks. Counting from the breeding date, fawning is normal anywhere from day 187 to day 222.

Key checkpoints across the 200-day white-tailed deer gestation, measured in days from breeding:

Estimate your white-tailed deer's fawning date

Enter the breeding date for an estimated fawning date at 200 days.

Open the full White-tailed deer gestation calculator

White-tailed deer gestation stages, month by month

Signs a white-tailed deer is pregnant

• No visible change for the first few months, so wild pregnancies are rarely obvious until spring
• A blood test for pregnancy-specific protein B (PSPB) confirms pregnancy on farmed deer from about day 30 to 40
• Ultrasound by a vet confirms pregnancy and can often show twins
• The belly and flanks widen noticeably from early spring, especially with twins

Signs of approaching fawning

• Udder swelling and teats filling in the last week or two before fawning
• The doe separates from other deer, chases off last year's fawns and stays in one small area of dense cover
• Contact your vet if labour stalls, if the animal strains without progress, or if there is abnormal discharge before fawning begins.

What affects white-tailed deer gestation length

• Gestation averages about 200 days, close to six and a half months, so a doe bred in mid November usually fawns in late May or early June.
• Rut timing is set mainly by day length. Across most of the northern and midwestern United States and southern Canada, breeding peaks in November, which places the bulk of fawning in late May and June.
• Latitude matters: the further north, the tighter and more predictable the rut, because fawns born late have too little summer to grow before winter. In the far south the rut is spread out and can fall anywhere from autumn to late winter depending on the local herd's history.
• Twins are the most common outcome for healthy adult does in good habitat. Yearling does and does in poor condition more often carry a single fawn, and triplets occur but are uncommon.
• Fawn sex ratios sit close to 50:50 in most herds, and twins can be the same or opposite sex because each fawn comes from a separate egg.
• Doe fawns can breed in their first autumn when food is abundant; they tend to breed later in the rut than adult does, so their fawns arrive later the following summer.
• A doe that is not bred on her first heat cycles again about 28 days later. Late-bred does are the main reason some fawns are still being born in July or August.
• Nutrition affects how many fawns survive more than it changes the gestation length. Does on a poor diet in late winter tend to have lighter fawns and weaker twins.

White-tailed deer gestation chart

Every fifth breeding date across the year with the matching fawning date, calculated at 200 days. Find the row closest to the date the white-tailed deer was served; because normal gestation spans 187 to 222 days, plan for a window of a few days either side. Filter by month, or print the chart for the barn wall or breeding record: navigation, buttons and adverts are hidden on paper.

Sources for white-tailed deer gestation figures

Figures on this page are drawn from state wildlife agency deer biology pages, university extension guidance on white-tailed deer and farmed deer, and National Deer Association research summaries, and checked against the references below. Averages describe healthy animals under normal management; individual animals vary, and nothing here replaces advice from your vet.

• National Deer Association — rut timing and fawning research summaries
• Penn State Extension — white-tailed deer biology and farmed deer management
• State wildlife agency deer biology pages (e.g. Pennsylvania Game Commission, Texas Parks and Wildlife)
• Mississippi State University Deer Lab
• Association of Zoos and Aquariums (AZA) — species husbandry and animal care manuals
• Smithsonian's National Zoo & Conservation Biology Institute — species fact sheets
• Published zoological studies of captive births