Exhibit 99.3

Innovating Women’s Reproductive Health and Pregnancy Therapeutics October    2017

Disclaimers    Matters discussed in this presentation may constitute forward-looking statements. The forward-looking statements contained in this presentation reflect our views    as of the date of this presentation about future events and are subject to risks, uncertainties, assumptions, and changes in circumstances that may cause our actual results, performance, or achievements to differ significantly from those expressed or implied in any forward-looking statement. Although we believe that the expectations reflected in the forward-looking statements are reasonable, we cannot guarantee future events, results, performance, or achievements. Some of the key factors that could cause actual results to differ from our expectations include our plans to develop and potentially commercialize our product candidates; our planned clinical trials and preclinical studies for our product candidates; the timing of and our ability to obtain and maintain regulatory approvals for our product candidates; the extent of clinical trials potentially required for our product candidates; the clinical utility and market acceptance of our product candidates; our commercialization, marketing and manufacturing capabilities and strategy; our intellectual property position; and our ability to identify and in-license additional product candidates. For further information regarding these risks, uncertainties and other factors that could cause our actual results to differ from our expectations, you should read our Annual Report on Form 20-F for the year ended December 31, 2016, as filed with the Securities and Exchange Commission on April 21, 2017 and our other filings it makes with the Securities and Exchange Commission from time to time. We expressly disclaim any obligation to update or revise the information herein, including the forward-looking statements, except as required by law. Please also note that this presentation does not constitute an offer to sell or a solicitation of an offer to buy any securities. This presentation concerns products that are under clinical investigation and which have not yet been approved for marketing by the U.S. Food and Drug Administration. It is currently limited by federal law to investigational use, and no representation is made as to its safety or effectiveness for the purposes for which it is being investigated. The trademarks included herein are the property of the owners thereof and are used for reference purposes only. Such use should not be construed as an endorsement of such products. This presentation also contains estimates and other statistical data made by independent parties and by us relating to market size and growth and other data about our industry. This data involves a number of assumptions and limitations, and you are cautioned not to give undue weight to such estimates. In addition, projections, assumptions and estimates of our future performance and the future performance of the markets in which we operate are necessarily subject to a high degree of uncertainty and risk. Proprietary and Confidential Material 2    

Proprietary and Confidential Material Strategic Focus: Large populations with high unmet medical need & limited competition    Age 15+ Age 15—Age 49 Age 50+    ObsEva Focus    Uterine Fibroids    Oral Contraception Anti-Infectives Pregnancy Supplements OTC / Generics Endometriosis Infertility Preterm Labor Preeclampsia    Menopause Symptoms Hormone Replacement Therapy Osteoporosis Generics / Innovation by Big Pharma                Proprietary and Confidential Material * Source: IMS Health Incorporated estimate as of 2015. Proprietary and Confidential Material * Source: IMS Health Incorporated estimate as of 2015. 3

Robust late-stage pipeline for women’s reproductive health & pregnancy PRODUCT PRECLINICAL PHASE 1 PHASE 2 PHASE 3 STATUS & NEXT COMMERCIAL CANDIDATE MILESTONE RIGHTS US/EU Phase 2b Endometriosis OBE2109* Data mid-2018 Worldwide Oral GnRH US/EU Phase 3 ex-Asia receptor antagonist Uterine Fibroids Primary Endpoint Data 2H 2019 NOLASIBAN EU Phase 3 IVF Oral oxytocin Worldwide receptor antagonist Data 1Q 2018 OBE022 Preterm Labor EU Phase 2a Oral PGF Worldwide 2á Data 4Q 2018 receptor antagonist Proprietary and Confidential Material * Kissei Pharmaceutical developing for Asia 4

Unique mix of clinical and operational experience provides in-depth understanding of patient & physician needs Ernest Loumaye, Tim Adams Jean-Pierre Gotteland, PhD Elke Bestel, MD Ben T.G. Tan, MSc MD, PhD, OB/GYN CFO CSO CMO VP Commercial & BD CEO and Co-founder A team of 30+ with successful experience in world-wide development and commercialization of women health products ObsEva is listed on The NASDAQ Global Select Market and trades under the ticker symbol “OBSV” 5    

ObsEva at-a-glance: Highly Focused Approach OBE2109: Potential best-in-class oral gonadotropin-releasing hormone (GnRH) Best-in-class GnRH antagonist receptor antagonist NOLASIBAN (OBE001): Potential to significantly improve clinical pregnancy and live birth rates after in vitro fertilization (IVF) Compelling pipeline OBE022: potential first-in-class therapy to suppress preterm labor and delay or avoid preterm birth Sizable target indications with Targeting indications with millions of underserved patients globally significant unmet need Multiple programs with significant potential OBE2109: Phase 2b EDELWEISS endometriosis data mid-2018 Multiple near-term data catalysts NOLASIBAN: Phase 3 IMPLANT2 data 1Q18 OBE022: Initiating Phase 2a PROLONG trial 4Q17, initial data 4Q18 Highly experienced management Management team has strong track record of successfully in-licensing, developing team and commercializing treatments for women’s reproductive health and pregnancy Proprietary and Confidential Material 6    

OBE2109 for Endometriosis and Uterine Fibroids 7

OBE2109: Potential best-in-class, oral, GnRH receptor antagonist with and without add-back therapy OBE2109 AT-A-GLANCE OBE2109 INDICATIONS • GnRH Receptor Antagonist • Uterine Fibroids • OBE2109 (KLH-2109) • Symptoms: Heavy menstrual bleeding and abdominal pain • Licensed from Kissei (WW rights, excludes Asia) • Primary goal is to reduce/eliminate bleeding • IP Protection* to 2036 (COM 2032) • Endometriosis • > 750 female subjects exposed to date • Symptoms: pain and infertility • Primary goal is to alleviate pain COMPETITION Standard of Care: Esmya® Elagolix Relugolix Lupron, approved in EU for (AbbVie/Neurocrine) (Myovant/Takeda) in oral contraceptives, surgery uterine fibroids in Phase 3 Development Phase 3 Development Proprietary and Confidential Material * Including PTA/PTE (Patent Term Adjustment / Patent Term Extension) 8    

Unmet medical need in endometriosis & uterine fibroids therapy LARGE U.S. MARKET SIZE Seeking to unlock Uterine Fibroids Endometriosis Another 2.5 MILLION 4 MILLION WOMEN 2.5 MILLION WOMEN diagnosed and Undiagnosed due to non-~200K treated annually specific symptoms and invasive diagnosed and treated annually Surgeries laparoscopy (Hysterectomy) Annually LUPRON® INJECTIONS cause flares, initial worsening of symptoms, no titration possible, OLDER, prolonged and variable reversibility time SUBOPTIMAL EXISTING ORAL TREATMENTS CONTRACEPTIVE SURGICAL and progestin, only INTERVENTIONS partially effective, costly, invasive, side safety risks effects Proprietary and Confidential Material 9    

OBE2109 consistent PK/PD profile with low variability, high bioavailability & low volume of distribution in Phase 1 PK/PD trial MEAN OBE2109 LH REDUCTION FROM CONCENTRATION OVER TIME BASELINE OVER TIME 1,000,000 200 Mean±SEM Mean±SEM • Half life = 15h: OBE2109 12.5 mg OBE2109 12.5 mg once a day OBE2109 25 mg OBE2109 25 mg OBE2109 50 mg 175 OBE2109 50 mg dosing 100,000 OBE2109 100 mg OBE2109 100 mg OBE2109 200 mg Hormone OBE2109 200 mg • Low volume of (ng/mL) OBE2109 400 mg 150 OBE2109 400 mg Placebo distribution 10,000 (Vd 11 L): No 125 dose adjustment Luteinizing for weight Concentration 1,000of 100 Baseline) • No food effect (% observed 75 Plasma 100 • No significant differences Concentration 50 between women OBE2109 10 of Japanese and Relative 25 European descent 1 0 0 4 8 12 16 20 24 0 4 8 12 16 20 24 Time (hr) Time (hr) Proprietary and Confidential Material 10    

OBE2109 potential best in class Optimal PK/PD & dual dosing options OBE2109 ELAGOLIX* RELUGOLIX* Half-Life 14-15 hours 2-6 hours 37-42 hours Bioavailability > 80% 30 – 50 % 11% Active transport limiting absorption Inhibitor & Saturable PK No substrate Substrate (PgP) Volume of distribution 11 L >2,000 L >20,000 L Observed characteristics Fat accumulation No Yes Yes +++ Food Effect No Yes Yes CYP3A4 induction (possible No Inducer & sensitive substrate No adverse impact on ABT) High dose with ABT Moderate dose without ABT Moderate dose without ABT Endometriosis – Dosing options (same dose 3 months only High dose with ABT High dose with ABT options w/o ABT) Moderate dose without ABT Uterine Fibroids – Dosing options High dose with ABT High dose with ABT Dose High dose with ABT ABT: Add Back Therapy 11 Proprietary and Confidential Material *Based on publicly available information and data for these other product candidates currently in development    

Potential benefits of GnRH antagonists vs GnRH agonists (e.g. Lupron) 1 No initial flare with worsening of symptoms, rapid reversibility 2 Oral dosing enhances patient compliance 3 Allows for partial estrogen suppression 4 Two dosage options to better meet individual needs 5 More suitable for chronic therapy Proprietary and Confidential Material 12    

OBE2109 Phase 2b clinical trial (EDELWEISS) in patients with endometriosis Primary endpoint: Key secondary pain scores endpoint: BMD 12 weeks Placebo 12 weeks 8–14 weeks 50 mg daily 50 mg daily 24 weeks LEAD-IN 75 mg daily 75 mg daily FOLLOW-UP 100 mg daily 100 mg daily 200 mg daily 200 mg daily Optional extension 75 mg daily* * Titrated dose 50–100 mg 6 m + 6m f-up * Titration after 12 weeks based on E2 serum level at weeks 4 and 8 Target enrollment of 330 patients • ~70 sites in US (up to 75% of patients) • 15 sites in EU (Ru, Ukr, Pl) IND granted in June 2016 Recruitment completed in EU – Ongoing in the US Proprietary and Confidential Material 13

OBE2109 Phase 3 clinical trials (PRIMROSE) in patients with uterine fibroids began April 2017 Primary endpoint: 8–14 weeks 24 weeks 28 weeks 24 weeks Reduction of HMB 16-OBE2109-008 Placebo + placebo add-back 100% US sites n = 100 Placebo + placebo add-back 200mg + add-back n = 100 100mg + placebo add-back 100mg + placebo add-back 24w follow-up n = 100 Screening 100 mg + add-back 100 mg + add-back n = 100 200 mg + placebo add-back 200 mg + add-back n = 100 200 mg + add-back 200 mg + add-back 16-OBE2109-009 70% Europe 30% US sites n = 100 Placebo + placebo add-back 200mg + add-back n = 100 100mg + placebo add-back 100mg + placebo add-back n = 100 24w follow-up Screening 100 mg + add-back 100 mg + add-back n = 100 200 mg + placebo add-back 200 mg + add-back n = 100 200 mg + add-back 200 mg + add-back IND granted in April 2017 Currently recruiting • Aiming at supporting the registration of two regimens of administration 14

NOLASIBAN to Improve IVF Outcomes 15

NOLASIBAN (OBE001): Oral oxytocin receptor antagonist to improve IVF outcomes NOLASIBAN AT-A-GLANCE NOLASIBAN INDICATIONS • Oxytocin Receptor Antagonist • In Vitro Fertilization (IVF) • Licensed from Merck Serono • Market size: 1.6 M ART/IVF cycles/year globally (~210K in US in 2014, • IP Protection to 2035-2036 ~620K in Europe in 2012 and ~325K in Japan in 2012) • ART cycle cost: $8-15K in the US, EUR 2-10K in the EU and $3-6k in • (COM 2027 with PTE) Japan • Estimated global sales of fertility drugs > 2 bn USD* COMPETITION Atosiban (Tractocile®) Barusiban Ph2 marketed ex-US for Pre term labor (IV only) SC injection twice/day Well-characterized profile, Phase 2 clinical trial completed  >650 subjects  Orally active - tmax at 2h;  Single oral dose of 900 mg OBE001 observed to exposed Well tolerated t1/2= 12h; High increase the live birth rate up to 51% compared to 31% bioavailability in the placebo group Proprietary and Confidential Material 16 * Source: IMS Health Incorporated estimate as of 2015.

ART procedures and options for embryo transfer (ET) Fresh Embryo Transfer ET Day 3 50% ET Day 5 25% Medical need for assisted reproductive technology Frozen Embryo for FET • 11% of couples present with infertility • IVF process has an overall live birth rate between ~21% and 33% • NOLASIBAN (OBE001) has the potential to be the first-in-class orally available oxytocin antagonist 25% Proprietary and Confidential Material 17

Oxytocin receptor is a validated target for improving pregnancy & live birth rates in ART Oxytocin X Oxytocin Receptor Comparative, randomized trials on the use of Atosiban prior to ET in ART Smooth Uterine Arteries Endometrium Meta-analysis of 6 studies* (Huang et al. 2017) Muscle Lining Cells n = 1754 Uterine Endometrium Atosiban CPR 51.2% Contractions Receptivity Control CPR 40.7% p < 0.001 Uterine Blood Flow Increase Clinical Pregnancy and Live Birth Rates * No of embryos transfered: 1 – 4 Proprietary and Confidential Material 18

Nolasiban Phase 2 Efficacy Results Absence of Dose Response FULL ANALYSIS RESULTS Nolasiban Nolasiban Nolasiban Nolasiban PLACEBO TREND TEST 100 mg 300 mg 900 mg All doses Number of subjects 65 62 60 60 182 Clinical pregnancy rate at 33.8% 46.8% 35.0% 46.7% 42.9% p=0.33 6 weeks after ET day Ongoing pregnancy rate at 29.2% 43.5%* 35.0% 45.0%* 41.2% p=0.15 10 weeks after OPU day Live birth rate 29.2% 40.3% 35.0% 43.3% 39.6% p=0.20 (baby born alive ³ 24 weeks gestation) Relative change in uterine contractions 0.0% -8.7% -4.0% -13.3%** *p£0.10 **p£0.05, Nolasiban vs Placebo Proprietary and Confidential Material 19

Nolasiban Phase 2 results: Efficacy (post-hoc analysis) On-going pregnancy rate (10 weeks) Live birth rate 60% (Trend test: p=0.035) (Trend test: p=0.025) rate 50% birth 40% live and 30% 20% Pregnancy 10% 0% N = 49 N = 50 N = 35 N = 49 100 mg 300 mg 900 mg Placebo Nolasiban Nolasiban Nolasiban Excluding subjects in progesterone 4th quartile at baseline Proprietary and Confidential Material 20

NOLASIBAN Phase 3 clinical trial (IMPLANT2): Recruitment of patients completed Main Study Primary Analysis Follow-Up 1 month 10 weeks 10 weeks Not preg. FU 900 mg, n=380 D3 or D5 SCREENING ET Placebo, n=380 7–8 months 6 months Preg.* Randomize Preg. FU Neonatal FU n=314 * Estimate Target enrollment of 760 patients • Trial being conducted in Europe First patients randomized in March 2017 – Recruitment completed in August 2017 Proprietary and Confidential Material Note: N=760 gives 90% power to show significant difference if the true effect size is 11-12%. It will still show a significant 21 effect if the observed size is about 6-7%.

OBE022 for Preterm Labor 22

OBE022: Potential first-in-class, oral and selective PGF2α receptor antagonist for preterm labor (PTL) OBE022 AT-A-GLANCE OBE022 INDICATIONS • Prostaglandin F2α (FP) receptor antagonist • Preterm labor (GA 24-34 week) • Licensed from Merck Serono • Incidence: USA: 500,000; EU: 500,000; Asia: 6,900,000* • Economic burden for premature infants: ~$26 billion in the U.S. ($16.9 • IP Protection through 2037 billion in infant medical care) • (COM 2037 with PTE) COMPETITION No drug approved for acute use in the US; atosiban used in the EU; Progesterone indicated for prevention in the US Phase 1 & DDI clinical trials completed • Oral administration • Favorable preclinical study outcomes Proprietary and Confidential Material * WHO ‘Born Too Soon: The Global Action Report on Preterm Birth’ 2012) 23

Antagonism of PGF2α receptor has potential to treat PTL with improved safety over NSAIDs Phospholipids Phospholipids ‘Inflammation’ Arachidonic Acid Prostaglandins Arachidonic Acid Indomethacin Cytokines PGHS-1/2 = COX1/2 PGHS-1/2 = COX1/2 Chemokines PGH2 PGH2 OBE022 PGE2 PGF2α PGE2 PGF2α EP1 EP2 EP1 EP2 FP FP EP3 EP4 EP3 EP4 UTERUS: UTERUS: CONTRACT RELAX CONTRACT CONTRACT RELAX CONTRACT kidney, brain, vascular smooth muscle PGF2α contracts the myometrium and RUPTURE PGF2α metabolites rise in amniotic fluid Vasoconstriction of ductus arteriosus, before and during labor renal and mesenteric arteries Platelet aggregation inhibition CONTRACT PGF2α upregulates enzymes causing cervix dilatation and membrane rupture DILATE Proprietary and Confidential Material 24

Phase 1/DDI results for OBE022 PHASE 1 SINGLE and MULTIPLE ASCENDING DOSES (SAD/MAD) • Healthy women volunteers, single and multiple doses over 7 days • Favorable safety profile and well-tolerated up to 1,300 mg single and 1,100 mg daily for 7 days (highest tested doses) PHASE 1 DRUG INTERACTIONS WITH BETAMETHASONE AND MgSO4 SOC TO IMPROVE NEONATE OUTCOME DURING PRETERM LABOR • No clinically relevant interactions PHASE 1 DRUG-DRUG INTERACTIONS WITH ATOSIBAN, NIFEDIPINE, i.e. tocolytics • No clinically relevant interaction with Atosiban • Nifedipine exposure increased by co-administration with OBE022 NEXT STEPS • Phase 2a PROLONG study in women with PTL, expected to initiate in 4Q 2017 Proprietary and Confidential Material 25

2017 Accomplishments and 2018-19 Expected Milestones Milestone Timing OBE022 (Preterm labor): Phase 1 DDI 2Q 2017 OBE2109: Phase 1 PK/PD add-back study data 2Q 2017 OBE2109 (Uterine fibroids): Initiation of US/EU Phase 3 trials-PRIMROSE 1 and 2 1H 2017  NOLASIBAN (IVF): Initiation of European Phase 3 IMPLANT2 trial 1H 2017 OBE2109 (Endometriosis): Completed EDELWEISS trial EU patient enrollment 2Q 2017  NOLASIBAN (IVF): Completed IMPLANT2 trial recruitment 3Q 2017 OBE022 (Preterm labor): Initiate Phase 2a PROLONG proof-of-concept clinical trial 4Q 2017 NOLASIBAN (IVF): IMPLANT2 Phase 3 primary endpoint data 1Q 2018 OBE2109 (Endometriosis): Phase 2b EDELWEISS data Mid-2018 OBE022 (Preterm labor): Initial Phase 2a PROLONG data 4Q 2018 OBE2109 (Uterine fibroids): Primary endpoint data PRIMROSE 1 and 2 trials 2H 2019 Proprietary and Confidential Material 26