Female dogs usually go into heat for the first time at around 6–12 months of age, then about twice a year (roughly every 6 months), with each heat lasting around 2–3 weeks.

Quick Scoop: Key Facts

  • Most female dogs have their first heat between 6 and 12 months old; small breeds can start as early as 4–6 months, large and giant breeds may not cycle until 18–24 months.
  • After that, they typically go into heat about every 6 months (2 times per year), though some small breeds may cycle 3 times yearly and some large or special breeds (like Basenji, Tibetan Mastiff) only once a year.
  • Each heat (season) usually lasts around 2–3 weeks, with bleeding and discharge often seen for 12–20 days.
  • Dogs do not go through menopause; they can continue having heat cycles for life unless they are spayed.
  • Spaying stops heat cycles completely and helps prevent certain health problems like pyometra and some reproductive cancers.

Mini Sections

When do female dogs first go into heat?

  • Most female dogs reach sexual maturity and have their first heat at 6–12 months.
  • Small breeds may start as early as 4 months; giant breeds may not have a first season until 18–24 months.
  • Vets often say the first heat appears 2–3 months after the dog reaches her adult body size.

How often do they go into heat?

  • Typical pattern: about every 6 months (around twice per year).
  • Small breeds: sometimes every 4–6 months, up to 3 times per year.
  • Large/giant breeds and certain breeds (e.g., Basenji, Tibetan Mastiff): sometimes only once a year.

How long is a dog in heat?

  • Overall heat/season: about 2–3 weeks, sometimes up to 4 weeks.
  • Bloody discharge phase (what most owners notice): commonly 12–20 days.
  • Many dogs are most fertile in the middle part of the heat, when discharge becomes lighter and more watery.

Signs your female dog is in heat

  • Swollen vulva.
  • Bloody or pinkish vaginal discharge that may become lighter over time.
  • More frequent urination and “marking” small amounts in many spots.
  • Behaviour changes: clinginess or restlessness, seeking male dogs, sometimes more vocal or agitated.

Many forum discussions from recent years echo the same experience: owners suddenly notice a bit of blood on the floor or bedding, then increased attention from neighborhood male dogs over the next couple of weeks, fitting this 2–3 week timeline.

Basic care and “latest” practical tips

  • Keep her away from unneutered males during the whole heat to avoid unplanned pregnancy.
  • Use doggy diapers, washable pads, or extra throws on furniture to manage discharge and keep things clean.
  • Walk her on a leash only; male dogs can be very persistent and may appear from far away.
  • Offer a quiet, comfy resting area, plus good nutrition and plenty of water; appetite may go up or down.
  • Talk to your vet about the best age for spaying if you don’t plan to breed, as current veterinary guidance (updated through 2025) continues to recommend spaying to prevent serious uterine infections and reduce some cancer risks.

Simple HTML table (for your post)

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<table>
  <thead>
    <tr>
      <th>Question</th>
      <th>Short answer</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>When do female dogs first go into heat?</td>
      <td>Usually between 6–12 months old, earlier for small breeds and later (up to 18–24 months) for giant breeds.[web:1][web:3][web:4][web:6][web:7]</td>
    </tr>
    <tr>
      <td>How often do they go into heat?</td>
      <td>About every 6 months (twice a year); some small breeds up to 3 times, some large breeds only once yearly.[web:1][web:4][web:5][web:7][web:9]</td>
    </tr>
    <tr>
      <td>How long does a heat last?</td>
      <td>Typically 2–3 weeks, sometimes up to 4 weeks, with bleeding around 12–20 days.[web:1][web:3][web:4][web:5][web:7]</td>
    </tr>
    <tr>
      <td>Do dogs ever stop going into heat?</td>
      <td>No natural menopause; they keep cycling for life unless spayed.[web:4][web:7]</td>
    </tr>
    <tr>
      <td>What if I don’t want puppies?</td>
      <td>Keep her away from entire males during heat and ask your vet about spaying to prevent pregnancy and some health risks.[web:1][web:3][web:4][web:6][web:7]</td>
    </tr>
  </tbody>
</table>

Quick TL;DR

Female dogs usually go into heat first between 6–12 months of age and then around every 6 months for 2–3 weeks at a time, with some variation by breed size.

Information gathered from public forums or data available on the internet and portrayed here.