The Depo-Provera® shot takes about seven days to become fully effective at preventing pregnancy. During this time, the hormone builds up in your body, suppresses ovulation, and thickens cervical mucus to block sperm. If you get your first shot within the first five days of your period, you’re protected right away—but if not, waiting the full week is essential to ensure pregnancy protection.
Nurx offers Depo-SubQ Provera® 104, a form of the Depo shot that provides the same pregnancy protection when used as directed.
What is the Depo® shot?
The Depo-Provera® shot (or Depo-SubQ Provera® 104) is an injectable form of birth control given every 12–13 weeks in your arm or buttock. It contains progestin, a hormone that prevents pregnancy by stopping ovulation, thickening cervical mucus so sperm can’t reach an egg, and thinning the uterine lining. When taken on schedule, it’s over 99% effective at preventing pregnancy.
How long until the Depo® shot fully kicks in?
If you receive your injection during the first five days of your menstrual cycle, the Depo-Provera® shot works immediately. If you get the shot at another time in your cycle, it takes seven days for the hormone to reach protective levels, which is why backup contraception is needed during that week.
Why does the Depo® shot take seven days to work?
Your body needs time to adjust to the progestin in Depo-Provera® (or Depo-SubQ Provera® 104). Over the course of seven days, the medication fully suppresses ovulation, prevents your ovaries from releasing an egg, and thickens cervical mucus enough to create a reliable barrier against sperm.
What are the risks of skipping the waiting period?
Having unprotected sex before the seven days are up can increase your chance of pregnancy because the shot may not be fully effective yet. This can lead to:
- Unintended pregnancy
- The need for emergency contraception
- Added stress and anxiety.
Using backup contraception during this period is the safest way to stay protected.
Can you get pregnant two days before a Depo® shot?
Yes. If it’s been longer than 13 weeks since your last Depo-Provera® shot, protection may wear off, and ovulation could return. Having unprotected sex even a few days before your next injection could put you at risk of pregnancy. If you’re overdue, use a backup method and schedule your shot as soon as possible.
How can I stay protected during the seven days?
During the 7 days after switching birth control, you’ll need backup protection to stay safe from pregnancy. Options include:
- Male or female condoms: a reliable, easily available option.
- Spermicide: for extra protection with your barrier methods.
- Abstinence: choosing to avoid sex until your birth control is fully effective.
- Emergency contraception (if needed): consider this if you’ve had unprotected sex before your new method becomes effective.
Using one of these methods ensures continuous protection while your new contraceptive takes effect.
How to handle protection gaps after your Depo® shot
If you’re worried about timing or missed protection, you don’t have to figure it out alone. Nurx providers can help you understand how Depo-Provera® (or Depo-SubQ Provera® 104) works, recommend backup methods when needed, and guide you toward the right birth control plan for your body and lifestyle.
Everything can be managed online, and your medication is delivered straight to your door for convenience and peace of mind.
The information provided is not a substitute for professional medical advice, diagnosis, or treatment. You should not rely upon this content for medical advice. If you have any questions or concerns, please talk to a medical professional.
Services not offered in every state. Medications prescribed only if clinically appropriate, based on completion of the required consultation. Individual results may vary.
Depo-SubQ Provera 104® (medroxyprogesterone acetate injectable suspension, 104mg/0.65mL for subcutaneous use), Rx only, is used as contraception to prevent pregnancy. This drug may cause side effects, including dysfunctional uterine bleeding (irregular, increase, decrease, spotting), headache, and weight gain. Meningiomas have been reported after repeated administration of medroxyprogesterone acetate, primarily with long-term use. Patients using this form of birth control should be monitored for signs and symptoms of meningioma, and treatment should be discontinued if a meningioma is diagnosed. If you would like to learn more, see full prescribing information, here. Depo-SubQ Provera 104® may be prescribed by a Nurx affiliated provider but is not fulfilled through a Nurx pharmacy.