Birth control can cause dozens of different side effects, ranging from mild nuisances like spotting and headaches to rare but serious events like blood clots. The exact number and type depend heavily on which method you use. Hormonal options (the pill, patch, ring, shot, implant, and hormonal IUDs) share a common set of roughly 10 to 15 recognized side effects, while the copper IUD has a shorter but distinct list. Most side effects are temporary, fading within three to five months as your body adjusts.
Common Side Effects Across Hormonal Methods
All hormonal contraceptives work by altering your hormone levels, so they share a core group of side effects. The most frequently reported include nausea, breast tenderness, headaches, spotting between periods, lighter or missed periods, mood changes, decreased sex drive, and bloating. Not everyone experiences all of these, and many people notice only one or two. The American Academy of Family Physicians notes that these symptoms usually diminish to the point of acceptance within three to five months of starting a method, so doctors often recommend waiting at least that long before switching.
How Side Effects Differ by Method
While the broad categories overlap, each delivery method has its own profile.
The Pill, Patch, and Ring
These combined hormonal methods (containing both estrogen and progestin) tend to cause nausea, headaches, breast tenderness, and breakthrough bleeding most often in the first few months. The patch can also cause skin irritation at the application site. One advantage: combined methods often improve acne. In a meta-analysis of 32 trials with over 3,200 women, oral contraceptives reduced total acne lesions by about 55% at six months, matching the results of oral antibiotics.
The Hormonal IUD
Hormonal IUDs release progestin locally into the uterus, so systemic side effects like nausea and headaches are less common than with the pill. The main side effects are cramping and back pain in the days after insertion, irregular spotting in the first few months, and lighter periods over time. Some people stop getting periods altogether. However, a large study found a positive association between use of a hormonal IUD and depression, anxiety, and sleep problems in women who didn’t have those conditions before.
The Implant
The arm implant’s signature side effect is unpredictable bleeding. In a study of 350 implant users, 59.4% reported abnormal bleeding patterns. Only about 15% experienced no periods at all. Most users without regular monthly cycles still had manageable bleeding (fewer than 16 days of bleeding or spotting over a 90-day window), but roughly 10% bled for more than 45 out of 90 days. Other side effects include headaches, mood changes, and breast tenderness.
The Shot
The injectable contraceptive carries most of the same hormonal side effects but adds two notable ones: weight gain and bone density loss. In studies comparing the shot to the copper IUD, shot users gained about 2.3 kg (5 lbs) more in the first year and 3.2 kg (7 lbs) more by year three. The FDA’s label carries a boxed warning that users “may lose significant bone mineral density,” with spine and hip density dropping 5 to 6% over five years of use. That loss only partially recovers after stopping. In adolescents who used the shot for more than two years, hip bone density had not fully returned to baseline even five years later.
The Copper IUD
Because it contains no hormones, the copper IUD doesn’t cause mood changes, acne, nausea, or any of the hormone-related effects. Its side effect list is shorter but distinct: heavier periods, longer periods, and worse menstrual cramps, especially in the first three to six months. Some users also experience cramping and back pain right after insertion. For people whose primary concern is avoiding hormonal side effects, it trades one set of issues for another.
Mood and Mental Health Effects
Mood changes are among the most discussed side effects of hormonal birth control, and large-scale data supports the concern. A Danish study following more than one million women found an increased risk of a first depression diagnosis and first antidepressant use among oral contraceptive users. The risk was highest among adolescents. This doesn’t mean hormonal birth control causes depression in most users, but it does mean the connection is real and worth paying attention to, particularly if you have a history of mood disorders or notice a clear shift after starting a new method.
Rare but Serious Risks
The most significant rare side effect of combined hormonal contraceptives (those containing estrogen) is venous thromboembolism, or blood clots. Among women not using hormones and not pregnant, the background rate is 1 to 5 clots per 10,000 women per year. For oral contraceptive users, that rises to 3 to 9 per 10,000. Certain pill formulations carry higher risk than others: pills containing older progestins like levonorgestrel carry about half the clot risk of newer formulations containing desogestrel or drospirenone. The contraceptive patch carries the highest risk among combined methods, at roughly 9.7 events per 10,000 women per year.
To put this in perspective, pregnancy itself raises clot risk far more than any contraceptive does. But the risk isn’t zero, and it increases further if you smoke, are over 35, or have a personal or family history of clotting disorders.
Protective Effects That Offset Some Risks
Side effects aren’t all negative. Long-term oral contraceptive use is linked to meaningful reductions in several cancers. Women who have ever used the pill have a 30% to 50% lower risk of ovarian cancer, at least a 30% lower risk of endometrial cancer (with greater reductions the longer they took it), and a 15% to 20% lower risk of colorectal cancer. These protective effects persist for years after stopping. Three specific pill formulations are also FDA-approved for treating moderate to severe acne in adolescents and women.
Weight Gain: What the Data Shows
Fear of weight gain is one of the most common reasons people avoid or stop birth control, but the evidence is more nuanced than the reputation suggests. For most hormonal methods, average weight gain at 6 to 12 months was less than 2 kg (about 4.4 lbs) in clinical studies, and in many trials, weight change didn’t differ significantly from a comparison group using non-hormonal methods. The clear exception is the shot. In one long-term retrospective study, shot users gained 6.6 kg (14.5 lbs) over 10 years compared to 4.9 kg in copper IUD users. The difference was most pronounced in women who started at a normal or slightly overweight BMI, and less notable among those who were already obese.
What the Adjustment Period Looks Like
If you’re in your first few months on a new method and dealing with spotting, nausea, or mood shifts, the standard recommendation is to give it three to five months before deciding the method isn’t right for you. Most side effects peak early and then taper. That said, if what you’re experiencing feels severe or significantly affects your quality of life, there’s no rule that says you must wait it out. There are enough contraceptive options available that finding one with a tolerable side effect profile is a reasonable goal, not a luxury.