What Is Ovarian Drilling and How Does It Treat PCOS?

Ovarian drilling is a surgical procedure that uses heat or laser energy to puncture small holes in the outer shell of a polycystic ovary, destroying a portion of the androgen-producing tissue and often restoring ovulation in women with PCOS who haven’t responded to first-line fertility medications. It evolved from a much older and more aggressive surgery called ovarian wedge resection, and today it occupies a specific niche in PCOS treatment: a second-line option when oral ovulation-induction drugs fail but before moving to injectable hormones or IVF.

Why PCOS Stops Ovulation in the First Place

To understand what ovarian drilling fixes, it helps to know what goes wrong in the ovary during PCOS. The ovaries of women with PCOS overproduce androgens (male-type hormones like testosterone). This happens because the theca cells that line the ovarian follicles overexpress the enzymes responsible for androgen production, particularly one called cytochrome P450c17.¹ The excess androgen inside the ovary promotes the early growth of many small follicles at once but then prevents any single follicle from maturing to the point where it releases an egg. The result is the classic polycystic appearance on ultrasound: a ring of stalled follicles, each roughly two to five millimeters across, none of them large enough to ovulate.²

Those stalled follicles also secrete high levels of anti-Müllerian hormone (AMH), which itself further interferes with follicle selection and the ovary’s response to the hormonal signals that normally trigger ovulation. Meanwhile, the pituitary gland pumps out extra luteinizing hormone (LH), which feeds even more androgen production. It’s a self-reinforcing loop: too much androgen, too many small follicles, too much AMH, too much LH, and no ovulation.

From Wedge Resection to Ovarian Drilling

The idea of surgically treating polycystic ovaries dates back to 1935, when Irving Stein and Michael Leventhal described removing roughly one-third of each ovary through open abdominal surgery. In their original series of 108 patients, regular menstrual cycles returned in 95% and the pregnancy rate was 85%.³ Those results were dramatic, but the surgery had a serious downside: cutting away that much tissue through an open incision caused extensive scar tissue (adhesions) around the ovaries and fallopian tubes, sometimes canceling out the fertility benefit. Some women even experienced premature ovarian failure from the tissue loss.

Ovarian drilling emerged in the 1980s as a far less destructive alternative. Instead of removing a wedge of tissue, a surgeon uses a laparoscope (a thin camera inserted through a small incision near the navel) and applies a needle-tipped instrument to make a series of small punctures in the ovary’s surface using either electrocautery or laser. Each puncture destroys a tiny cylinder of androgen-producing tissue. The goal is the same hormonal reset that wedge resection achieved, with far less collateral damage.

How the Procedure Is Performed

Ovarian drilling is done under general anesthesia. The surgeon inserts the laparoscope through one small incision and one or two additional instruments through other small incisions in the lower abdomen. Carbon dioxide gas is used to inflate the abdomen and create a working space. The ovary is held steady, and a monopolar or bipolar cautery needle is used to puncture the ovarian capsule at several points, typically four to ten per ovary. Some surgeons use laser energy instead of electrical energy, though electrocautery is more common. A bipolar technique, which limits the spread of thermal energy, has also been described.⁴

The amount of energy applied at each puncture and the number of punctures vary among surgeons, and there is no universally agreed-upon protocol. Most practitioners try to minimize the total thermal dose while still achieving enough tissue destruction to shift the hormonal balance. The surgery itself takes roughly 20 to 30 minutes, and most patients go home the same day. Recovery is generally faster than from open abdominal surgery, with most women returning to normal activity within a few days.

What Happens Hormonally After Drilling

The punctures destroy a portion of the androgen-secreting theca tissue and the small stalled follicles within the ovary. This kicks off a cascade of hormonal changes. One study tracked women for six months after the procedure and found testosterone levels dropped by about 30% within three months and 33% by six months, while LH levels fell by roughly 28% and 35% over the same intervals. AMH levels also declined, by about 16% at three months and 25% at six months. FSH levels, meanwhile, stayed roughly stable.⁵

The drop in AMH is a useful marker. In PCOS, AMH is abnormally elevated because of all those small follicles, and the high AMH itself blocks follicle maturation. Bringing it down helps restore the normal selection process where one follicle dominates and proceeds to ovulate. Research on a newer transvaginal approach to ovarian ablation found that the women who successfully ovulated after the procedure were the ones whose LH and testosterone dropped the most, while non-responders maintained higher levels.⁶

A separate study of 50 women showed that testosterone, LH, and the LH-to-FSH ratio all dropped significantly after drilling, and menstrual cycles became regular in 82% of the group. Hirsutism and acne also improved.⁷ These cosmetic and menstrual improvements matter to many women with PCOS beyond the fertility angle, though drilling is rarely performed for those reasons alone.

How Long the Effects Last

One concern with any hormonal intervention is whether the benefits are temporary. Ovarian drilling appears to produce changes that persist for years. A long-term follow-up study found that the LH-to-FSH ratio, serum LH, testosterone, and free androgen index all decreased significantly after drilling and remained low through both medium-term and long-term follow-up. Mean ovarian volume dropped from 11 mL before the procedure to 8.5 mL at medium-term follow-up and stayed at 8.4 mL long-term.⁸ This durability is one of drilling’s genuine advantages over medications that only work for the cycle in which they’re taken.

Fertility Outcomes

The question most women care about is whether drilling leads to pregnancy. The numbers are encouraging but not overwhelming. In one review, roughly 71% of women ovulated after drilling, and pregnancy rates ranged from 25% to 51%, with live birth rates of 24% to 44%.⁹ A study of 289 patients found that about 47% achieved a pregnancy after drilling, with roughly half of those pregnancies occurring spontaneously and the other half after additional ovulation-induction medication. The overall live birth rate was around 40%.¹⁰

Another study reported that about 77% of women ovulated after drilling, with a live birth rate of 47%. On average, ovulation returned within about 79 days, and pregnancy occurred within about 241 days for those who conceived.¹¹ The spread in these numbers reflects differences in patient populations, surgical technique, and whether additional medications were used after drilling. Some women who don’t ovulate spontaneously after drilling become responsive to clomiphene or letrozole, medications that previously failed them, which is a real advantage of the procedure even when drilling alone doesn’t do the trick.

Who Is a Good Candidate

Ovarian drilling is positioned as a second-line treatment, meaning it’s considered after first-line oral medications have failed. Current guidelines recommend letrozole as the first-line ovulation induction agent for PCOS, with clomiphene citrate as an alternative.¹² When women don’t ovulate on these oral drugs (termed “clomiphene-resistant” or “letrozole-resistant”), the next options include injectable gonadotropins, ovarian drilling, or IVF.

Drilling tends to work best in women who are not severely overweight and whose primary issue is anovulation rather than other concurrent fertility problems. Women with very high baseline LH levels appear to be poorer responders, based on evidence that those who don’t ovulate after the procedure tend to maintain elevated LH compared with responders.⁶ Insulin resistance doesn’t appear to change after drilling itself, which means women with significant metabolic issues may need metformin or lifestyle modifications alongside the procedure.¹³

How Drilling Compares to Medications

The most relevant comparison is between drilling and the other second-line options: injectable gonadotropins and letrozole (when used after clomiphene failure). A systematic review and meta-analysis of randomized controlled trials comparing letrozole to ovarian drilling in clomiphene-resistant women found no significant differences in ovulation rate, pregnancy rate, live birth rate, or miscarriage rate between the two approaches.¹⁴ Individual studies within that analysis sometimes showed slight edges one way or the other, with some finding somewhat higher ovulation rates with letrozole and somewhat higher miscarriage rates with drilling, but none of these differences were statistically significant.¹⁵

Compared to gonadotropin injections, drilling produces similar live birth rates but with important safety differences. Gonadotropin therapy carries risks of ovarian hyperstimulation syndrome (OHSS) and multiple pregnancies (twins or more), because it’s difficult to control exactly how many follicles develop. A comparative study found that while the gonadotropin group had the highest rates of OHSS and multiple pregnancies, the laparoscopy group had the lowest, though the differences didn’t reach statistical significance in that particular study.¹⁶ Another study noted that when drilling was supplemented with clomiphene or gonadotropins afterward, pregnancy rates became equivalent to gonadotropin therapy alone, but with a lower risk of multiple pregnancies.¹⁷

Cost is another factor in drilling’s favor. A scoping review of cost-effectiveness studies found that all three studies comparing ovarian drilling to gonadotropin therapy concluded drilling resulted in cost savings with no significant difference in outcomes.¹⁸ Gonadotropin cycles require repeated ultrasound monitoring, blood tests, and the medication itself, all of which add up over multiple cycles.

Risks and Complications

Ovarian drilling is a surgical procedure, and it carries real risks that deserve honest discussion. The most studied complication is adhesion formation: scar tissue that develops around the ovaries and fallopian tubes after surgery. A second-look study using minilaparoscopy found adhesions in 60% of the women examined and on 46% of ovaries treated. Dense adhesions were more likely to develop on the left side, and the number of punctures didn’t appear to predict adhesion severity.¹⁹ These adhesions can theoretically impair fertility by trapping the ovary or interfering with tubal function, and at least one study has raised the concern that even women who become pregnant after drilling may show significant adhesions when their abdomens are opened at cesarean section.²⁰

The other common concern is whether drilling damages the ovarian reserve, the pool of eggs available for future fertility. AMH levels do drop significantly after drilling, as confirmed by a meta-analysis of over 400 patients.²¹ However, interpreting this drop is tricky. AMH is abnormally high in PCOS to begin with, because of all the excess small follicles. The drop after drilling may represent the desirable normalization of AMH rather than genuine depletion of the egg supply. One study specifically concluded that while AMH falls significantly after drilling, the procedure was not associated with diminished ovarian reserve.²² The meta-analysis authors themselves acknowledged that it remains uncertain whether the AMH decline reflects real ovarian damage or just normalization of inflated pre-operative levels.²¹

The general surgical risks of laparoscopy also apply: infection, bleeding, injury to surrounding organs, and reactions to anesthesia. These are uncommon but not zero. Premature ovarian failure (running out of eggs too early) has been described after ovarian wedge resection, the older and more aggressive procedure, but has not been a documented pattern with modern drilling when performed with reasonable restraint on the number and depth of punctures.³

Metabolic Effects Beyond Fertility

PCOS is more than just an ovulatory disorder; it often comes with insulin resistance, elevated cholesterol, and increased cardiovascular risk. Some studies have examined whether drilling improves these metabolic markers. One study comparing drilling with metformin found that both approaches produced significant declines in testosterone, LH, and insulin-like growth factor-1, and that the glucose-to-insulin ratio improved after drilling.²³ However, another study looking specifically at insulin resistance found that the HOMA index, a measure of how resistant the body is to insulin, didn’t change after drilling.¹³ The picture here is mixed: drilling seems to improve some hormonal markers related to metabolism, but it’s not a metabolic treatment in the way metformin or lifestyle changes are. Women with significant insulin resistance should not expect drilling to address that part of the PCOS picture.

Transvaginal Ovarian Drilling

A newer variation avoids laparoscopy altogether. Ultrasound-guided transvaginal ovarian needle drilling (UTND) uses a needle passed through the vaginal wall under ultrasound guidance to puncture the ovaries, similar in concept to the egg retrieval procedure done during IVF. It can be performed in an outpatient clinic setting without general anesthesia.²⁴ Proponents argue it offers a lower risk of adhesion formation because the abdominal cavity is never entered, along with reduced cost and faster recovery. Early evidence suggests ovulation and pregnancy rates are comparable to laparoscopic drilling, though the evidence base is still thin compared to the laparoscopic approach, which has decades of data behind it.

The appeal of the transvaginal route is obvious: no general anesthesia, no abdominal incisions, and potentially fewer adhesions. But gynecologists remain cautious. The technique requires precise ultrasound skills, and the long-term outcomes haven’t been studied as thoroughly. For now, it’s an option some centers offer, particularly for women who want to avoid general anesthesia or who have had prior abdominal surgeries that make laparoscopy more difficult.

Where Drilling Fits in a Treatment Sequence

Understanding where drilling belongs in the treatment ladder helps set realistic expectations. For most women with PCOS-related infertility, the sequence starts with lifestyle modifications (if overweight) and letrozole as the first-line drug.¹² Clomiphene citrate is another early option. If those don’t produce ovulation after several cycles, the second-line choices are ovarian drilling, gonadotropin injections, or jumping to IVF.

Drilling occupies a useful middle ground. It avoids the cycle-by-cycle monitoring and multiple-pregnancy risk of gonadotropins, costs less over time, and its hormonal benefits can persist for years, potentially making subsequent medication cycles more effective. On the other hand, it’s a surgery, with all the attendant risks. It’s also not repeatable in the same way drug cycles are: you can’t just do another round of drilling if the first one doesn’t work well enough, because additional thermal damage to the ovaries would compound the risks to the egg reserve.

This is the core trade-off every woman and her fertility specialist weigh. Drilling offers a one-time intervention with long-lasting hormonal effects and no risk of OHSS or twins, but it involves operating room risks, potential adhesion formation, and uncertain impact on ovarian reserve. Gonadotropins offer a non-surgical option with cycle-by-cycle flexibility, but at higher cost, greater monitoring burden, and the specific risks of hyperstimulation. The clinical evidence says both paths lead to similar pregnancy and live birth rates in appropriately selected patients, so the decision often comes down to individual circumstances, access, and preference.

1
PubMed Central. The Pathogenesis of Polycystic Ovary Syndrome (PCOS): The Hypothesis of PCOS as Functional Ovarian Hyperandrogenism Revisited
2
PubMed. The follicular excess in polycystic ovaries, due to intra-ovarian hyperandrogenism, may be the main culprit for the follicular arrest
3
Fertility and Sterility. Modern trends Laparoscopic treatment of polycystic ovaries: is it time to relinquish the procedure? – Section: Ovarian wedge resection
4
Fertility and Sterility. Techniques and instrumentation Laparoscopic ovarian drilling using a 5-French bipolar energy probe
5
European Journal of Cardiovascular Medicine. Impact of Laparoscopic Ovarian Drilling on Ovarian Reserve, Hormonal Profile, and Fertility Outcomes in Clomiphene Citrate Resistant Women with Polycystic Ovarian Syndrome – Section: Results
6
Human Reproduction. L26/O-318 Transvaginal ovarian ablation using a novel system for PCOS-related infertility: effectiveness and exploratory hormonal associations from the ULTRA trials
7
PubMed Central. Laparoscopic Ovarian Drilling Reduces Testosterone and Luteinizing Hormone/Follicle-Stimulating Hormone Ratio and Improves Clinical Outcome in Women with Polycystic Ovary Syndrome – Section: Results
8
PubMed. Long-term follow-up of patients with polycystic ovary syndrome after laparoscopic ovarian drilling: endocrine and ultrasonographic outcomes
9
Hellenic Journal of Obstetrics and Gynecology. What Is Ovarian Drilling and How Does It Treat PCOS? – Section: Results
10
PubMed Central. Ovarian drilling in polycystic ovary syndrome: Long term pregnancy rate – Section: Results
11
Fertility and Sterility. Pregnancy rates after laparoscopic ovarian drilling in polycystic ovary syndrome patients following unsuccessful ovulation induction – Section: Results
12
PubMed Central. Laparoscopic ovarian drilling for ovulation induction in women with anovulatory polycystic ovary syndrome
13
PubMed. The impact of insulin resistance on the outcome of laparoscopic ovarian diathermy in women with polycystic ovarian syndrome
14
PubMed Central. Letrozole versus laparoscopic ovarian drilling in clomiphene citrate-resistant women with polycystic ovary syndrome: a systematic review and meta-analysis of randomized controlled trials
15
PubMed. Reproductive outcome after letrozole versus laparoscopic ovarian drilling for clomiphene-resistant polycystic ovary syndrome
16
PubMed Central. Comparative study of two ovulation induction therapies and laparoscopic ovarian drilling on clinical outcomes in women with clomiphene citrate-resistant polycystic ovary syndrome – Section: Results
17
Journal of South Asian Federation of Obstetrics and Gynaecology. To Study the Effect on Fertility Outcome by Gonadotropins vs Laparoscopic Ovarian Drilling in Clomiphene-resistant Cases of Polycystic Ovarian Syndrome
18
PubMed Central. Cost-Effectiveness of Interventions Related to the Treatment of Women With Polycystic Ovary Syndrome: A Scoping Review – Section: OI Using Gonadotropins Compared to Laparoscopic Ovarian Drilling (LOD)
19
PubMed. Evaluation of ovarian adhesion formation after laparoscopic ovarian drilling by second-look minilaparoscopy
20
Sri Lanka Journal of Obstetrics and Gynaecology. Incidence of peri-tubal and ovarian adhesions following laparoscopic ovarian drilling (LOD) observed opportunistically at subsequent caesarean sections
21
PubMed. The impact of laparoscopic ovarian drilling on AMH and ovarian reserve: a meta-analysis
22
PubMed Central. Impact of laparoscopic ovarian drilling on serum anti-mullerian hormone levels in patients with anovulatory Polycystic Ovarian syndrome
23
International Journal of Gynecology & Obstetrics. Metformin versus laparoscopic ovarian drilling in clomiphene- and insulin-resistant women with polycystic ovary syndrome
24
PubMed Central. Ultrasound‐guided transvaginal ovarian needle drilling for clomiphene‐resistant polycystic ovarian syndrome in subfertile women